Ruben Spruijt

Microsoft releases App-V 4.6. Will this unlock your virtual potential?

Ruben Spruijt — Tue, 23 Feb 2010 05:00:00 GMT

Yesterday Microsoft released a new version of their application virtualization solution: App-V 4.6. In this article, Ruben Spruijt explains why application virtualization is the way to GO and what the new features of App-V 4.6 are (including the functionality of the new shared cache feature).

Application Virtualization, the way to GO!

Making applications available to end users is probably the most important functionality of an IT infrastructure, and in today's world, the dynamic delivery of applications is essential. In conversations with customers I regularly receive the question, “What is the difference between app deployment and app delivery?”

With application deployment, the applications are installed on the execution platform. The execution platform could be a local desktop. laptop, a central virtual desktop, a blade PC, or a Remote Desktop Server. When speaking of application delivery in the context of application virtualization, the applications are no longer installed. Instead, they're made almost instantly available and executed on the execution platform. The execution platform does not undergo any alterations.

Microsoft Application Virtualization (App-V) enables fast application delivery in both central and local environments whereby mutual application conflicts are excluded. This considerably reduces the throughput times of application packaging and delivery compared to the traditional deployment methods. The primary reasons for applying application virtualization are:

Applications are no longer installed on the (Virtual) desktops, laptops, or Terminal Servers
No more conflicts between applications
Eliminates the need for regression testing
Multiple versions of applications can be used simultaneously
Consolidation of Terminal Servers
Fast application delivery, roll-out, and upgrades
Stabilizes Windows profiles
Creates a dynamic application delivery infrastructure which allows applications to be used online, offline, on-site, off-site
Package once run 'everywhere'
Creates dynamic in a stateless VDI and Terminal Server environment

“Application Virtualization is the way to go!

What's new in App-V 4.6?

The new features in App-V 4.6 are:

Virtualizing Office 2010: If there was any doubt about virtualizing Office in the past it good to know that Office 2010 integrates much better with App-V 4.6. With the release of the Office Deployment Kit for App-V the following functionality is available:

Sharepoint integration; Open, Save, Edit files;
Use Outlook fast search to send and find emails quickly;
Print documents directly to OneNote
Send files directly from inside of the Office products;
Document Indexing is used to find content
RSS feeds and Open web based calendar
Virtual Mail applet in control panel

64-bit OS and Application support: App-V now supports x86 and x64 bits applications on x86 and x64 operating systems. The support of x64 operating systems is valuable for local desktop and laptops running Windows 7, and for Terminal Server environments running Windows Server 2008R2

Support for Windows 7 Applocker and Bitlocker: App-V integrates with Applocker, branchCache, Applocker ToGo and Bitlocker ToGo.

Improved Sequencer experience: The App-V sequencer is able to package/sequence both x86 and x64 applications with the same tool. The process of sequencing applications is easier than before.

Reduce disk storage in VDI/RDS scenario: The new App-V shared cache features reduce the amount of storage in a Virtual Desktop Infrastructure (VDI) environment. The pros and cons about this will be explained in the next chapter.

The App-V shared cache

App-V 4.6 now supports the ability to configure the App-V client to use the package cache as a read-only file. This capability was added to support multiple App-V client machines access to a single package cache this functionality is very useful in Server Hosted Virtual Desktops (VDI) and Remote Desktop Services (Terminal Services) scenarios. With VDI there is a big impact on (central) storage. The IO and capacity increases while using vDesktops. Storage needs much attention while designing and maintaining a VDI environment. Microsoft App-V shared cache functionality will decrease the storage capacity impact. The App-V package cache normally exists inside of a file with .FSD filename extension.

The FSD file must be placed in a location that can be accessed by the vDesktops; the location of the package cache should have read-only access and should perform well. Direct Attached Storage (DAS)) or central (SAN) storage will meet the storage criteria.

Publishing and Streaming

The package cache should be configured prior the publishing step. Any method of publishing a virtual application to the App-V client can be used. When a package is published to the App-V client it will immediately show as 100% loaded in the package cache. Despite the fact that it will not be streamed, the SFT file must still be made available to the App-V client via a streaming server. The client needs to read metadata stored inside the file. The type of streaming server must be an RTSP(S) server. IIS or SMB streaming servers are not supported. It should be clear that network traffic will be minimal since the SFT file itself will not be streamed because the storage infrastructure is being used.

Sharing the cache and store the SFT files

There are two ways to share the FSD file.

Inside a mounted VHD mapped as a drive. If the FSD file is shared inside its own VHD, that VHD will be mounted as a drive e.g. E: in the master VDI VM image.
As a UNC on a “share” that is accessible by all vDesktops.

The SFT file that is used to populate the shared package cache must be placed on an RTSP(S) streaming server. All client configuration options can be used including such options as the Application Source Root (ASR). The SFT file(s) will not be streamed since it will already be fully cached inside the FSD; the App-V client will only access the SFT in order to retrieve the required metadata. The streaming functionality of the App-V Management Server can be used for this purpose.

Populating the App-V cache

In order to populate the shared package cache, the use of an authoring client machine is recommended. This is (virtual) machine that has the App-V client installed normally. An administrator uses any streaming method they choose to import an SFT file into the FSD file. Once the FSD file on the authoring client has been populated it must be copied off in order to be shared by the vDesktop VMs. To do this, the Application Virtualization Client service must be disabled on the authoring client, the authoring client machine rebooted, and the FSD file copied off.

Managing Package Upgrades

As virtual application packages are upgraded the FSD file will require updates as well. If the master VDI VM uses a UNC to specify the filename, the FSD file update can be made with no change to the VDI VM master by specifying a symbolic link in the master VDI VM image Filename. When the FSD file is updated, only the filename that the symbolic link references must be updated i.e. the symbolic link will need to be updated to reference the new FSD file. The clients will continue to use the same-named symbolic link and thus require no update.

Bottom line; the shared cache feature will save in (central) storage capacity costs. The impact on disk-IO and the real-life experiences while updating applications in a shared cache will prove the value of App-V 4.6 shared cache!

Questions or comments please let me know: rsp@pqr.nl

Related information:

Understanding how storage design has a big impact on your VDI! http://www.brianmadden.com/blogs/rubenspruijt/archive/2009/12/10/vdi-and-storage-deep-impact.aspx

Desktop virtualization and the power of App-V and Windows 7 http://www.brianmadden.com/blogs/rubenspruijt/archive/2010/02/22/desktop-virtualization-and-the-power-of-windows-7.aspx

Application Virtualization Solutions Overview and Feature Compare matrix http://www.brianmadden.com/blogs/rubenspruijt/archive/2009/06/28/application-virtualization-solutions-overview-and-feature-compare-matrix-v2-2.aspx

Desktop virtualization and the power of App-V and Windows 7

Ruben Spruijt — Mon, 22 Feb 2010 17:00:00 GMT

Many organizations are on the verge of revamping their existing workstation concept or even replacing them altogether. Windows 7 is therefore a logical realization for many organizations. With the most recent virtualization solutions, the ‘classic’ use of Windows 7 on rich clients is, according to Ruben, not a matter of course; it can also be done in a different way. Desktop virtualization has developed into a serious, attractive and effective desktop delivery platform. In this article, Ruben Spruijt outlines the five different desktop virtualization concepts, the role of Windows 7 and Microsoft App-V within these concepts and the MED-V and XPM solutions for Windows 7.

Application and desktop delivery

If there is a trendy word in the IT industry, then, as well as Cloud Computing, this has to be ‘virtualization’. Virtualization is nothing more than the decoupling detachment of IT resources. The forms of virtualization that are most frequently applied include network, storage, hardware/server, desktop and application virtualization. The virtualization of desktops can be subdivided into five different concepts. The objective of these concepts is to provide the user with a ‘desktop’ upon which web-architected and windows applications can be executed. Desktop Virtualization is a significant component in the entire range of solutions concerning making ranges of applications available to end-users. Application and desktop delivery is a process which has the goal of offering applications independent of location and workstation, so that the user can work onsite, online, offsite and offline anywhere and at any time.

When studying and determining which solution best suits the users and your organization, it is essential that you ask yourself two questions:

What is the execution platform for the applications?
Within the execution platform, system resources such as the CPU, memory, disc and network are used in order to execute the Windows and web-architected applications. The most frequently used implementation platforms include the following: Desktop, Laptop, Mobile Internet device, Virtual Desktop Infrastructure and Remote Desktop Services. The choice of implementation platform is the most fundamental decision made! The applications are executed locally on the device or centrally in a computing centre. Every implementing platform has its own characteristics. In practice, every organization actually possesses a mixture of workstation access scenarios. The theories: “Less is more” and “Cut out the exceptions” should always be borne in mind!
In what way are applications made available on the execution platform?
An execution platform is great, especially with Windows 7, but if there are no applications available on this platform, this platform is of no real value to the end-user. The second question is this: How do the applications (which are critical for the company) get onto the implementation platform?! A number of solutions exist for making Windows applications available on the implementation platform. The forms that are most frequently used include installation or virtualization. With installation, applications are automatically installed on the workstation and, where possible, installed in an unattended manner, within the scope of which the implementation platform, the workstation, is adapted. The installation of the application in a base image is also one of the possibilities available. When applications are made available by means of virtualization, these are available ‘on demand’ on the implementation platform. No adjustments are made to the execution platform within the scope of this.

Application Virtualization is an essential and indispensable component for all desktop delivery solutions and server-hosted VDI in particular. The description of the functional value, the impact on the infrastructure and the specific properties of the various Application Virtualization solutions is an interesting subject for a new article.

Desktop virtualization x5

Making applications available to the end-user, separately from the technology used, is the ultimate strategic aim of an ICT infrastructure! The Virtual Desktop (vDesktop) is an essential component in the range of Application and Desktop delivery solutions and in essence, provides the following functions:

Flexibility: Detach the vDesktop from the endpoint
Flexibility: Several vDesktops next to one another
Access: vDesktop works independently of location, endpoint and network
Access: Uniform workstation
Security: Server Hosted – VDI; data in the computing centre
Freedom: Every user has their own desktop
Management: Hardware-independent ‘image’
Legacy: It is simple to offer legacy applications on a state-of-the-art platform
Sustainability: Power Management, handling the necessary resources in an efficient manner.

Desktop Virtualization is the separation of the desktop, the operating system and the applications from the underlying endpoint. This form of virtualization can be subdivided into two types: With the first type of virtualization, the end-user applications are executed remotely, server hosted, and presented at the endpoint via a Remote Display Protocol. With the second type of Desktop Virtualization solution, the applications are executed at the endpoint, client-side, and presented locally on this workstation. If we study the two virtualization concepts in more detail, five different types of Desktop Virtualization can be defined, these include:

Client-side (executed locally) bare-metal client hypervisor
Client-side (executed locally) client-hosted hypervisor
Server-hosted (executed remotely) shared desktop
Server-hosted (executed remotely) personal virtual desktop
Server-hosted (executed remotely) personal physical desktop

A graphic overview of the five different desktop virtualization solutions can be found in Figure 1.

Figure 1; Overview of the Desktop Virtualization solutions

Overview of the Desktop Virtualization solutions

The five different Desktop Virtualization solutions and the role of Windows 7 are outlined in the following paragraphs.

Remote Display Protocol

The Remote Display Protocol in Windows 7 and Server2008R2 plays an essential role for the server-hosted desktop virtualization solutions. RDP 7 supplies the end-user with the following: Aero support, DirectX remoting, Multi-monitor support, Multimedia Redirection and bi-directional audio. In practice, the end-users’ experience is positive, especially in a LAN scenario. Optimization for 2D/3D, Flash and Silverlight applications is not yet available.

Server hosted shared remote desktops, RDS

Desktop Virtualization, by means of ‘Server hosted shared remote desktops’, is a solution for gaining remote access to desktops and applications that are executed on a Remote Desktop Server (RDS) in the data centre. Access to the desktop or application is not connected to a location or end-user equipment and the execution of the programme takes place centrally on the server. The information appears on the client's screen via a remote display protocol such as Microsoft RDP or Citrix ICA/HDX. Every user has his/her own desktop session but shares the computer platform with other users. Other frequently used terms for this type of desktop virtualization include the following: Terminal Services, Remote Desktop Servers (RDS) and Session or Presentation Virtualization. Suppliers of ‘Server hosted shared remote desktops’ solutions include, for example, Microsoft, Citrix (XenApp) and Quest (vWorkspace).
Microsoft Windows 7 is a ‘single user’ client operating system; however a multi-user operating system is required for this type of desktop virtualization. Therefore no role has been set aside here for Windows 7. However, the Remote Display Protocol of Windows Server2008R2 is comparable with that of Windows 7. It is, for example, possible to use Windows Media Player, SilverLight, Flash and DirectX with the Microsoft RDP7 protocol and experiences with this have been positive (especially in a LAN environment).

Server Hosted Personal Remote Virtual Desktops, VDI

Server hosted Personal Remote Virtual Desktops is a solution for gaining remote access to Windows 7 or legacy Windows XP desktops that are executed on a virtual machine in the datacentre. The Virtual Infrastructure does not operate using hardware and ensures availability and manageability. Other frequently used terms for this type of desktop virtualization include the following: Virtual Desktop Infrastructure (VDI) or Server Hosted Virtual Desktops (SH-VDI). The use of Server hosted VDI does not require the Windows XP/7 vDesktop to be connected to a location or item of end-user equipment. Each user has his/her own unique, personal and completely isolated workstation. Programme execution, data processing and data storage take place centrally on the personal desktop. The information is displayed on the client’s screen via a remote display protocol such as Microsoft RDP, Citrix ICA/HDX or VMware ‘PC-over-IP’, to name but a few. Suppliers of overall solutions for ‘Server Hosted Personal Virtual Remote Desktops’, for example, include Microsoft (RDS-V), VMware (View), Citrix (XenDesktop) and Quest (vWorkspace).
The importance of Microsoft Windows 7 with this type of desktop virtualization is to supply a Remote Display Protocol (RDP7) and a state-of-the-art client operating system.

Stateless and Statefulll Desktops

Stateless and Statefull are essential terms, especially in relation to server-hosted remote personal desktops. It is important to understand what these two terms mean.

Stateless Desktops: In practice, a number of different terms are used for stateless desktops; pooled, none-persistent or standard desktops are frequently-used terms. The essence is the same, the virtualized desktop is and will always remain clean and ‘pristine’; therefore ‘stateless'. All machine-related modifications, for example applications that are installed by a user, are removed when the user logs off. User-specific settings that are recorded in the user profile, however, can be stored and re-used. In addition to the aforementioned benefits of Desktop Virtualization, stateless desktops also offer the following specific properties:

The simple roll-out and update of basic images
A virtual desktop is guaranteed to be 100% identical
The user always has the same (clean) workstation
Less effort is required by the management team due to the standardization of images.

Stateful Desktops: In practice, a number of different terms are used for Stateful desktops, including assigned, persistent or private desktops; terms that are frequently used. The essence is the same, the user is and will always remain connected to a vDesktop on a 1:1 basis. When the user has the freedom to install software, the machine-related adjustments continue to be maintained within this desktop, which is where the term ‘Stateful’ is derived from. In addition to the aforementioned benefits of Desktop Virtualization, a Stateful desktop therefore has a specific property, namely:

Freedom to install software within the desktop, for example.

An important point of special interest with regard to Stateful desktops is the fact that the roll-out phase, update, upgrade and security of the operating system and the applications is less simple to manage than with the stateless desktops. The impact on (central) storage is also greater than with stateless desktops. So, which is better, stateless or Stateful?! The answer to this question depends on the functionality that the end-users require and the impact of this functionality on the ICT department.

Server Hosted Personal Remote Physical Desktops

An optimum experience has not yet been gained by the end-user with Remote Desktop Services and Server Hosted VDI when using graphic intensive 2D/3D, Next Gen and Unified Communications applications. A significant reason for this is the fact that the presence of graphic processor power is lacking in the virtual desktop. The server hosted personal remote physical desktop is the solution and offers users remote access to Windows 7 or legacy Windows XP desktops. These desktops are executed on a physical machine in the data centre. Costly blade (professional) workstations or PCs are frequently used for the physical machines. (Figure 2 is an example of a HP blade workstation solution).

Figure 2, blade workstation solution
The GPU in each blade ensures that every vDesktop is equipped with sufficient graphic processing power in order to be able to execute multimedia, 2D/3D, NextGen and Unified Communications applications. Monitor information is presented on the endpoint device via an optimized remote display protocol. In order to be able to present the information with the end-user gaining the best possible experience with this, additional requirements may be made with regard to bandwidth, latency or locally available (software) components. The expectation is that graphic performance in the physical desktop will become available in the Virtual Machines to some extent over time. Microsoft RDP in Windows7 can only make extremely limited use of the physically available GPU at present. The ‘Server Hosted Personal Remote Physical Desktops’ solution is supplied by HP, Citrix and Teradici, to name but a few.

Client-side Virtual Desktops, CS-VDI

Client-side desktop virtualization is a solution through which the Virtual Machine(s) is/are executed locally at the end point. The Hypervisor ensures that every virtual machine operates independently of hardware and renders it possible to utilize several Virtual Machines on the workstation at the same time. The hypervisor plays an essential role and can be subdivided into two categories, the ‘bare-metal’ category and a ‘client-hosted’ hypervisor.

The bare-metal client hypervisor is often referred to as Type#1, as this can be used directly from the hardware resources. The result of this is a ‘near-native’ performance.
The client-hosted hypervisor is installed as an application on the Windows, Apple or Linux operating system, and provides a broader level of hardware support. As this hypervisor is installed on the operating system, this is referred to as ‘Type #2’. The performance of the vDesktop is acceptable for the average user, but is definitely not maximal.

Citrix XenClient, VMware Client Virtualization Platform, Neocleus and Virtual Computer are bare-metal solutions. Microsoft VirtualPC, XPM, MED-V, VMware ACE- and Fusion, Parallels Desktop, Sun VirtualBox are client-hosted desktop virtualization solutions. The role of Windows 7 within client-side virtual desktops is primarily to provide a state-of-the-art client operating system. The Remote Display protocol is not applicable for the local execution of applications on the vDesktop.

XPM and MED-V

The ‘Windows XP mode for Win7’ (XPM) is a client-hosted ‘Type#2’ desktop virtualization application. This desktop virtualization function is already present in the Professional, Enterprise and Ultimate versions of Windows 7. Nevertheless, the objective of XPM is to make legacy applications that do not function (well) available on a Windows 7 workstation. The legacy applications are executed in the virtual machine and presented (under water via RDP) on the Windows 7 workstation.
XPM uses Microsoft VirtualPC, through which a number of specific integration functions are added. In order to be able to make use of XPM, the hardware from the endpoint must support the hardware-assisted virtualization method AMD-V, Intel-VT or VIA-VT in the CPU.
Microsoft Enterprise Desktop Virtualization (MED-V) is a desktop virtualization solution which many people are unfamiliar with. The function of MED-V can be compared in part with XPM, where XPM does not have any central management functions and MED-V excels in these. XP mode for Windows 7 is primarily of interest for single-users and small environments, whilst MED-V provides business and enterprise circles with the correct management functions. As is the case with the application of Microsoft application virtualization (App-V) on desktops or laptops, MED-V is a component of the Microsoft Desktop Optimization Pack (MDOP). Software Assurance is required for this purpose.

Desktop Virtualization; Good, Bad and Ugly?!

Despite a large number of benefits of desktop virtualization, a number of challenges should also be mentioned here. Providing answers to the questions below will provide assistance when studying the reality and feasibility of the various desktop virtualization solutions:

Is the virtualization concept and the solution proven? What is my definition of proven?!
What impact will there be on (central and local) storage? VDI + Storage = Deep Impact!
What is the end-user’s experience, what can one expect and will I be satisfied with this?
Will we make use of a stateless server-hosted VDI solution?
Teaser: A stateless Server Hosted VDI solution can be compared with a Remote Desktop Server (TS)  to a level of 90% in terms of its functions.
What does the application of desktop virtualization mean for my ICT organisation; do we have the correct skills and mindset?
How can I use offline desktop virtualization? Will I need to apply desktop virtualisation for this?
Do my end-users require total freedom on the workstation and, if so, why?
Do I have intensive resource and graphic applications? How do I go about offering these?
Do I possess the correct Microsoft (VECD) licences for my virtual desktops?
Who from the ICT management team is responsible for the virtual workstation?
What is the migration strategy?

Desktop virtualization offers a large number of functions, both for the end-users and for the ICT organization. A study into the functionality, impact, feasibility and the effect on TCO, is and will remain an essential component. It is possible to write a completely new article regarding the Good, the Bad and the Ugly of desktop virtualization. The Bad and Ugly are of particular interest :-) and would make an interesting subject for a further article.

Application Virtualization

Application Virtualisation enables Windows applications to be made available at a workplace without making changes to the operating system. Neither do you have to install the application at the workstation. In other words, even if the application is not locally installed you can simply run the application, save data with it and print. The local client does not have to be adapted.
Microsoft Application Virtualization (App-V) enables fast application delivery in a client-side and server-hosted environment whereby mutual application conflicts are excluded. This considerably reduces the throughput times of application packaging and delivery compared to the traditional deployment methods. There are various reasons for using Application Virtualization. The primary reasons for using Application Virtualization are:

Applications are no longer installed on the client-side or server-hosted machines;
No more conflicts between applications;
Eliminates the need for regression testing;
Multiple versions of applications can be used simultaneously;
Consolidation of Remote Desktop Services;
Fast application roll-out and upgrades;
Stabilises Windows profiles;
Creates a dynamic application delivery infrastructure which allows applications to be used online, offline, on-site, off-site, locally and centrally;
Empowers dynamic application delivery in a stateless server-hosted VDI and server-hosted Remote Desktop Services environment;
Makes image management easier; less core applications in base image.

There are two kinds of Microsoft App-V licenses, one for Remote Desktop Services and one for Desktop operating systems like Windows 7. Microsoft Desktop Optimization Pack (MDOP) which includes a total of six Desktop Optimization solution contains Microsoft App-V.

Application Virtualization and VDI

Server Hosted Virtual Desktops (VDI) is a fascinating concept of delivering desktops and applications to users. The pros and cons of this solution are already explained. While VDI provides important advantages, all resources come together in the datacenter. That means that the CPU resources, memory resources, networking and disk resources all need to be facilitated from a single point--the virtual infrastructure. The impact on capacity and I/O of storage in a Server Hosted Virtual Desktop scenario is big. Understanding how storage design has a big impact on your VDI os available: http://www.brianmadden.com/blogs/rubenspruijt/archive/2009/12/10/vdi-and-storage-deep-impact.aspx
Application Virtualization is an important component when designing and implementing VDI. Microsoft App-V version 4.6 now supports a shared cache functionality. This means that App-V Client is able to treat the package cache as a readonly file. This capability was added to support multiple App-V client machines or VMs access to a single package cache and saves on the storage capacity costs. A full description of the configuration can be found here: http://blogs.technet.com/virtualworld/archive/2010/01/20/getting-started-with-the-app-v-shared-cache-in-4-6-rc-part-1.aspx

Conclusion

Desktop virtualisation has developed into a serious, interesting and effective desktop delivery platform. Microsoft has a clear vision in the field of application and desktop delivery and fulfils a vital role in this with Windows7 and Server 2008R2. Many organizations are on the brink of replacing their existing workstations and a choice must be made between ‘traditional’ deployment or desktop virtualization. The point in time at which this moment will arise is different for everybody, but one thing is for certain and that is that this moment shall come! Users expect a higher level of flexibility, freedom and functionality from the workstation, whilst the IT organization places cost-reduction, manageability and compliancy high on its agenda. By using Windows 7, Application Virtualization and Desktop Virtualization, functions that were not previously possible (or were not very good) are now within reach. This article has outlined the various desktop virtualization solutions, the role of Windows 7 and the Power of Application Virtualization. The objective here was to provide a clear picture of the opportunities (and impossibilities) offered by desktop virtualization. “Power to the People, Windows 7 rocks!”

About the author

Ruben Spruijt works as a Technology Officer at PQR, a leading organization in the design, implementation and migration of advanced ICT infrastructures. In his role, Ruben primarily focuses on Virtualization and Application and Desktop Delivery. Ruben has given presentations at a number of conferences both within this country and overseas and has also published a number of different articles on this matter. These can be downloaded from www.virtuall.nl.

Follow Ruben on twitter? www.twitter.com/rspruijt; Any questions? If so, e-mail rsp@pqr.nl

Think today... change tomorrow?! Your step-by-step guide to moving today's apps into tomorrow's world

Ruben Spruijt — Mon, 15 Feb 2010 05:00:00 GMT

The adoption of Application Virtualization, Virtual Desktop Infrastructure (VDI), and the availability of Windows 7 create many new and interesting possibilities for the delivery of applications and desktops. Many organizations are on the threshold of a new or updated workplace concept. They're asking themselves how their workstations should look in the years to come. Users expect greater flexibility, freedom, and functionality of their workstations, whereas IT is focused on cost reductions, manageability, and compliance. In this article, Ruben Spruijt describes the three steps needed to make the correct Application and Desktop delivery choices. He also describes the tools available to help you examine whether applications are suitable for Windows 7, 64-bit technology, VDI and Application Virtualization. Ruben also describes the solution for converting ‘traditional MSI’ packages into virtualized application packages. But regardless of whichever approach or tools you use, one thing is certain: 2010 is the year of choices! “Think today… change tomorrow.”

The next step

Many organizations currently use traditional workstation solutions where Windows XP/Vista is installed on clients and applications are distributed and automatically installed by some sort of electronic software distribution (ESD) solution. (This ESD solution typically takes care of the installation of the operating system and any patches, asset management, and remote control functionality.) While nothing is actually wrong with the workstation solution described, the question is, "What is the next step for my organization?" Far-reaching developments in the field of Application Virtualization, Desktop Virtualization, Image Management, User workspace management, and Systems management mean that an updated (or new!) workstation concept is now within reach. This new workstation concept meets the functional requirements of the user more effectively while giving IT a better grasp of the application and desktop availability infrastructure.

Choices, choices, choices…!

Does a lot of choice lead to happiness or a headache? The question, and also the challenge, which many organizations are faced with today when it comes to Application and Desktop delivery is: 'Which supplier and product choices are there and which way should I go?'. For example: should we keep using a ‘traditional’ rich-client model, or should we change over to a ‘state-of-the-art’ Virtual Desktop? Will we install our applications, or virtualize them instead? Won't everything soon be web-architected anyway? What would be the best thing for us to do then? The answer to these questions depends on the requirements imposed by end users and the IT organization on the application and desktop delivery. An insight into both the requirements and functionality of the solutions is essential in order to make the right choices. The good news is that just a few simple questions allow us to make the correct fundamental choices for the right application and desktop delivery solution. The first question is:

Q: What is the execution platform of the applications?
In the case of the execution platform, system resources such as CPU, memory, disk and network are used to actually implement the Microsoft Windows and web-architected application. The most common implementation platforms are Desktop, Laptop, Smartphone, Server-hosted VDI, Client-side VDI and Terminal Services. The choice of implementation platform is the most fundamental choice. The applications are implemented locally on the device or centrally in a computing centre. An important question here is: “Where is the data?” as each implementation platform has its own characteristics. In practice, each organization actually has a mix of workstation access scenarios. The propositions “Less is more” and “Eliminate exceptions” must be kept in mind at all times! Well-known suppliers of these platforms include Microsoft, Citrix, VMware and Quest.

Q: How are the applications on the execution platform made available?
An execution platform is all well and good, certainly with the release of Windows 7, but if no applications are made available on this platform, it is of no use whatsoever to the end user. The second question to be asked when determining the future application and desktop delivery platform is: 'How will the (critical) applications be made available on the implementation platform?'. Various solutions exist for making Microsoft Windows applications available on the implementation platform. The most frequently-used forms are installation or virtualization. In the case of installation, applications are automatically installed (wherever possible in an unattended manner) on the workstation. Here, the implementation platform (the workstation) is modified. Installing the application in a basic image is also an option. If applications are delivered by means of virtualization, they are available ‘on-demand’ on the implementation platform. The implementation platform is not modified in this case. There are more than 8 different application virtualization suppliers. The most common are Microsoft, Citrix, VMware and Symantec.

Q: How are the execution platform and the applications on this platform managed?
The last question is: “How do we manage this mix of solutions?”. Traditional workstation management consists of various tasks. For example, the rollout of a (new) operating system, keeping this operating system up-to-date, insights into hardware and software usage and application installation all fall under PC lifecycle or device management. The focus of this management software is the device or endpoint. The use of user profiles, group policies and (logon/logoff) scripting, for example, traditionally constitutes the management of the ‘user workspace’. The focus in user workspace management is the end-user environment. To achieve an optimal workstation, a combination of device and user workspace management is important.
The developments and interest in User workspace management solutions have gained pace enormously in recent years. Functionalities such as profile, performance, configuration, security and access management are very important in the new (virtual) desktop of 2010. User workspace management creates separation between the user and the applications, while application virtualization creates separation between the application and the operating system. As a result of this separation, it makes no difference how the applications are delivered and where these applications are implemented, as long as the user is able to work with them. Various suppliers are offering specific functionalities of user workspace management. These suppliers include Microsoft, RTOSoft (VMware and Symantec have an OEM agreement with RTOSoft), Immidio, Scense and BrainForce. RES Software and Appsense provide a complete set of workspace management functionalities. So what is most suitable for me? In actual fact, the real question here is: “What user workspace management functionality does my organization need?”. A good subject for the next article...

Migration?

An answer to the three ‘simple’ questions can be obtained from workshops or knowledge-sharing sessions. At the end of this session - or sessions - it will be clear what application and desktop delivery can do for the organization and which functionalities the user will receive. Many questions will be answered during the abovementioned workshops. Examples which are of interest for this article include:

Will we use PCs or server-hosted VDI?
Will we use the 32-bit or 64-bit version of Windows 7?
Are my applications even suitable for Windows 7?
Which applications work on a 64-bit operating system?
Can I virtualise my applications?
How can I easily convert the existing application packages into a virtual format?

The first question has everything to do with the desired functionality of the implementation platform, the first of the three questions asked previously. The following paragraphs will mainly focus on the questions: “Are the applications ready for Win7/x64/AppVirt?” and “Can the applications be easily converted from MSI to a virtual application format?”. Migrating workstations, applications and data to a new or updated platform is an art. Nonetheless, the right tools make the migration process a lot easier.

Application Compatibility

For each migration, it is important to examine whether the applications are suitable for a new platform. The value of the research mainly lies in reducing the turnaround time and the risk involved in the migration. Various suppliers offer solutions for examining whether applications are suitable for a new platform. Microsoft, Acresso and Wise are three suppliers who can help you to examine whether applications are compatible. There are also suppliers such as AppDNA and Changebase who can provide extra help when it comes to checking whether applications are “Ready”. In practice, within PQR we use AppDNA. The value of AppDNA will be described below.

AppDNA Apptitude

AppDNA, the supplier of Apptitude, has developed software which examines the compatibility of existing applications with Windows 7, 64-bit Operating Systems, Application Virtualization and Desktop Virtualization, for example. The comprehensive knowledge and best practices which the AppDNA organization has gathered over the years have been incorporated into the Apptitude database. The Apptitude software uses the ‘DNA’ of the application and compares this with the information in the database. The existing applications are examined in a three-step process.

The first step, the import phase, ensures that the existing MSI is imported into the system as non-MSI based application packages.
The second step, the analysis phase, tests whether the applications are compatible. This research can be carried out in various different areas. The most obvious tests for this article are as follows: Application Virtualization, Desktop Virtualization, Compatibility for Desktop or Server operating system (Win7/2008R2) and x64 platform.
The third and last step in the process is the report phase. First of all, a global ‘traffic light’ overview is issued. The applications which are compatible are shown in green. The applications with minor compatibility challenges are shown in orange and the applications with major challenges in red. The global management overview shows in percentage terms which applications are green, orange or red. A (very) detailed report states which applications are orange or red and, more importantly, why they are not compatible. This gives an experienced packager or even the software development department the information needed to come up with a solution. Examining whether the applications are ready for the next step is important for each migration. Apptitude is a practical and valuable solution for this research.

Figure 1, AppDNA's three steps

Figure 2, Application Readiness ‘traffic lights’ overview

Application Conversion

Application Virtualization ensures that the applications can be offered on the workstation quickly, dynamically, simply and without conflicts. This form of virtualization creates a separation between the application and the operating system, which means that the workstation can be used in a more manageable and cost-efficient way. Between 85% and 95% of Microsoft Windows applications can be virtualized. The success ratio depends on two factors.

Firstly, which Application Virtualization supplier is used. Currently, there are more than 8 different application virtualization suppliers. Each supplier has its own vision, focus and features. The features offered by supplier A may not yet support, for example, Services, Side-by-Side (SxS) and .NET Framework. Applications which use these technologies cannot be virtualized as a matter of course.
Secondly, for example, there are virtualization limitations in the support for kernel mode drivers, deep OS integration etc.

If 95% of the applications can be virtualized, the (unattended) installation of applications is still required. This will also remain the case in the years ahead.
The question “But how do we convert our existing applications into a virtual application format?” is frequently heard. There are two ways to convert the existing application packages. The most common method at the moment is the repackaging of the application in a new virtual package format. Another, very interesting, method is the fully automated conversion of existing application packages. In particular, it takes much less time to convert an application automatically than to carry out the manual actions required in order to package the application. The suppliers of traditional packaging software are very active in the field of Application Virtualization. Acresso AdminStudio and WISE Packaging Studio make it possible to convert the existing .MSI files into a Virtual application format.

Figure 3, Acresso Admin Studio conversion wizard

Figure 4, support for App-V, ThinApp and XenApp

Depending on the supplier, conversion to Altiris/Symantec SVS, Citrix XenApp, Microsoft App-V and VMware ThinApp is possible. The success ratio of the conversion of existing application packages greatly depends on the quality of the existing packages. The technical features of the application virtualization solution also play an important role in the percentage of successful application conversions. In practice, conversion ratios of 60-70% are realistic. The combination of research into application compatibility and application conversion is very powerful. If the simple ‘green’ applications can be converted into a virtual application format in a fully automated manner, this has many advantages. The risk and turnaround time of these migration steps will then be greatly reduced.

Conclusion

Many organizations are about to replace their existing workstations. The arrival of Application Virtualization, Windows 7 and Desktop Virtualization has brought with it many new functionalities. Users expect greater flexibility, freedom and functionality of their workstations, whereas the IT organization sets store by cost reductions, manageability and compliance. Because of the use of Windows 7 in combination with Desktop Virtualization, Desktops and Laptops, the migration of applications to a new platform is a challenge. By means of AppDNA Apptitude, a solution which examines application compatibility, safe migration to a new or updated platform becomes simpler and less risky. The conversion of existing applications to a new virtual application format can take a great deal of time. By means of Acresso Adminstudio, for example, existing applications can be converted in a fully automated way in a short time, meaning that “Application Virtualization is THE way to go!”. With the right approach and the right tools, a migration to Windows 7, VDI and Application Virtualization need not present a problem or challenge, but an excellent opportunity to offer increased functionality whilst reducing costs. “Think today… change tomorrow!”

Understanding how storage design has a big impact on your VDI!

Ruben Spruijt — Fri, 11 Dec 2009 00:00:00 GMT

Introduction

Virtual Desktop Infrastructure, or VDI, is hot. It’s cool, secure, centrally managed, flexible--it’s an IT manager’s dream.

VDI comes in two flavors: Server-Hosted VDI (centralized, single-user remote vDesktop solution) and Client-Side VDI (local, single-user vDesktop solution).

The advantages of a VDI infrastructure are that virtual desktops are hardware independent and can be accessed from any common OS. It's also much easier to deploy virtual desktops and to facilitate the freedom that the users require of them. And because of the single-user OS, application compatibility is much less of an issue than it is with terminal servers.

However, when implementing a VDI infrastructure, certain points need to be addressed. First of all, the TCO/ROI calculation may not be as rosy as some people suggest. Secondly, the performance impact on applications--specifically multimedia and 3D applications--needs to be investigated. And finally, you have to deal with the licensing aspects, as this can be a very significant factor in VDI infrastructure.

While centralized desktop computing provides important advantages, all resources come together in the datacenter. That means that the CPU resources, memory resources, networking and disk resources all need to be facilitated from a single point--the virtual infrastructure.

The advantage of a central infrastructure is that when sized properly, it's more flexible in terms of resource consumption than decentralized computing. It's also more capable of handling a certain amount of peak loads, as these only occur once in a while on a small number of systems in an average datacenter.

But what if the peak loads are sustained and the averages are so high that the cost of facilitating them is disproportionate to that of decentralized computing?
As it turns out, there is a hidden danger to VDI. There’s a killer named “IOPS”.

The Client I/O

A Windows client running on local hardware has a local disk. This is usually an IDE or SATA disk rotating at 5,400 or 7,200 RPM. At that rate it can deliver about 40 to 50 IOPS.

When a Windows client starts, it loads both the basic OS and a number of services. Many of those services provide functionality that may or may not be needed for a physical system and make life easier for the user. But when the client is a virtual one, a lot of those services are unnecessary or even counter-productive. Indexing services, hardware services (wireless LAN), prefetching, and others all produce many IOPS in trying to optimize loading speed, which works well on physical clients but loses all effectiveness on virtual clients.

The reason for this is that Windows tries to optimize disk I/O by making reads and writes contiguous. That means that reading from a disk in a constant stream where the disk’s heads move about as little as possible is faster than when the head needs to move all over the disk to read blocks for random reads. In other words, random I/Os are much slower than contiguous ones.

While the amount of IOPS a client produces greatly depends on the services it’s running, it's even more dependent on the applications a user is running. Even the way applications are provisioned to the user impacts the IOPS they require.

For light users the amount of IOPS for a running system amounts to about three to four. Medium users show around eight to ten IOPS and heavy users use an average of 14 to 20 IOPS.

Now the most surprising fact: those IOPS are mostly writes. A great many researchers have tested the IOPS in labs and in controlled environments using fixed test scripts. The read/write ratio turned out to be as high as 10/90 as a percentage. But that's just a lab with a test script. In the real world, where users run dozens or even hundreds of different applications, the R/W ratio turns out to be 50/50 percent at best! In most cases the ratio is more like 70/30, often even 8020 and sometimes as bad as 90/10 percent!

Why does this matter? Most vendors don’t even mention IOPS or differentiate between reads and writes in their reference designs.

The Storage I/O

When all IOs from a client need to come from shared storage (attached directly to the virtualization host or through a SAN) and many clients read and write simultaneously, the IOs are 100% random (at least from the storage point of view.)

SCSI versus ATA

There are two main forms of disks: SCSI and ATA. Both have a parallel version (regular SCSI vs IDE or PATA) and serial version (SAS vs SATA). The main differences between the architecture of the SCSI and ATA disks are protocol and rotation speed. To start with the protocol, the SCSI protocol is highly efficient with multiple devices on the same bus, and it also supports command queuing. ATA devices have to wait on each other, making them slower when grouped together.

The higher rotation speed means that when the head needs to move to a different location, it does not need to wait as long for the data to pass beneath it. So a SCSI disk can produce more IOPS than an ATA disk. The faster a disk rotates, the less time the head needs to wait before data passes beneath it and the sooner it can move to the next position which is why it can handle more IOs per second.

To give some idea of the numbers involved; a 15,000 RPM disk can handle about 180 random IOPS, a 5,400 RPM disk about 50. These are gross figures and the number of IOPS that are available to the hosts depend very much on the way they are configured together and on the overhead of the storage system. In an average SAN, the net IOPS from 15,000 RPM disks is 30 percent less than the gross IOPS.

RAID Levels

There are several ways to get disks to work together as a group. Some of these are designed for speed, others for redundancy or anything in between.

RAID5

The way a traditional RAID5 system works is that it writes the data across a set of hard disks, calculates the parity for that data and writes that parity to one of the hard disks in the set. This parity block is written to a different disk in the set for every further block of data.

To write to a RAID5 system, the affected blocks are first read, the changed data is inputted, the new parity is calculated and the blocks are then written back. On systems with large RAID5 sets this means a write IO is many times slower than a read IO. Some storage systems, like HP’s EVA, have a fixed set of four blocks for which parity is calculated, no matter how many disks are in a group. This increases overhead on a RAID5 group because every set of four disks needs a fifth one, but it does speed things up. Also, on most storage systems, write operations are written to cache. This means that writes are acknowledged back to the writing system with very low latency. The actual write to disk process takes place in the background. This makes incidental write operations very speedy, but large write streams will still need to go directly to disk.

With 15,000 RPM disks the amount of read IOPS are somewhere in the 150-160 range while write IOPS are closer to the 35-45 range.

RAID1

A RAID1 set is also called a mirror. Every block of data is written to two disks and read from either one. For a write IO to occur, the data doesn’t need to be read first because it does not change part of a parity set of blocks but rather just writes that single block of data. This means that writing to a RAID1 is much faster than to a RAID5.

With RAID1 the data is read from one of the two disks in a set and written to both. So for 15,000 RPM disks, the figures for a RAID1 set are still 150-160 IOPS for reads, but 70-80 for writes.

RAID0

RAID0 is also called striping. Blocks of data are written in sequence to all disks in a RAID0 set but only to one at the time. So if one disk in the set fails, all data from the set of disks is lost. But because there is no overhead in a RAID0 set, it is the fastest way of reading and writing data. In practice this can only be used for volatile data like temporary files and temporary caches, and also perhaps for pagefiles.

If used, the amount of IOPS a RAID0 set can provide with 15,000 RPM disks is 150-160 for reads and 140-150 for writes.

RAID-DP

RAID-DP is a special version of RAID4 in the sense that it uses two instead of one parity disks. RAID4 is like RAID5 except that, instead of spreading parity across all disks, the parity is only written to one disk. RAID-DP uses two parity disks that contain the same data, so that failure of one disks does not require a rebuild of the parity (very storage- and CPU-intensive). This way, RAID-DP has the ability to survive the loss of any two disks. When a parity disk fails, a new disk simply needs to replicate the data from the other parity disk.

This technology is used with great efficiency in NetApp storage. The way the NetApp underlying filesystem works means that the data for RAID-DP doesn’t need to be read first before it can be written, making it as fast as RAID10 but with a level of resilience similar to RAID6.

So, with 15,000 RPM disks in a RAID-DP, the number of read IOPS per disk is some 150-160 but the number of write IOPS lies somewhere between 70-80 IOPS.

Disk Alignment

Because we want to minimize the amount of IOPS from the storage we want every IO to be as efficient as possible. Disk alignment is an important factor in this.
Not every byte is read separately from the storage. From a storage perspective, the data is split into blocks of 32 kB, 64 kB or 128 kB, depending on the vendors. If the filesystem on top of those blocks is not perfectly aligned with the blocks, an IO from the filesystem will result in 2 IOs from the storage system. If that filesystem is on a virtual disk and that virtual disk sits on a file system that is misaligned, the single IO from the client can result in three IOs from the storage. This means it is of utmost importance that all levels of filesystems are aligned to the storage.

Unfortunately, Windows XP and 2003 setup process misalign their partition by default by creating a signature on the first part of the disk and starting the actual partition at the last few sectors of the first block, misaligning the partition completely. To set this up correctly, create a partition manually using ‘diskpart’ or a Linux ‘fdisk’ and put the start of the partition at sector 128. A sector is 512 bytes, putting the first sector of the partition precisely at the 64 kB marker. Once the partition is aligned, every IO from the partition results in a single IO from the storage.

The same goes for a VMFS. When created through the ESX Service Console it will, by default, be misaligned. Use fdisk and expert mode to align the VMFS partition or create the partition through VMware vCenter which will perform the alignment automatically. Windows Vista and later versions try to properly align the disk. By default they align their partition at 1 MB, but it’s always a good idea to check if this actually is the case .

The gain from aligning disks can be 3-5 percent for large files or streams up to 30-50 percent for small (random) IOs. And because a VDI IO is an almost completely random IO, the performance gain from aligning the disks properly can be substantial. A quick way to check if a partition is aligned is by typing “wmic partition get BlockSize, StartingOffset, Name, Index” in a command shell. If the number isn’t a multiple of 65536 (64 kB) or 1048575 (1 MB) the partition is unaligned.

Prefetching and Defragging

The NTFS filesystem on a Windows client uses 4 kB blocks by default. Luckily, Windows tries to optimize disk requests to some extent by grouping block requests together if, from a file perspective, they are contiguous. That means it is important that files are defragged. However, when a client is running applications, it turns out that files are for the most part written. If defragging is enabled during production hours the gain is practically zero, while the process itself adds to the IOs. Therefore it is best practice to disable defragging completely once the master image is complete.

The same goes for prefetching. Prefetching is a process that puts all files read more frequently in a special cache directory in Windows, so that the reading of these files becomes one contiguous reading stream, minimizing IO and maximizing throughput. But because IOs from a large number of clients makes it totally random from a storage point of view, prefetching files no longer matters and the prefetching process only adds to the IOs once again. So prefetching should also be completely disabled.

If the storage is de-duplicating the disks, moving files around inside those disks will greatly disturb the effectiveness of de-duplication. That is yet another reason to disable features like prefetching and defragging.

The Math

So much for the theory. How do we use this knowledge to properly size the infrastructure?

Processor

On average, a VDI client can share a processor core with six to nine others. Of course, everything depends on what applications are being used, but let’s take an average of 7 VMs per core. With a dual socket, quad core CPU system that means we can house 7 x 2 x 4 = 56 clients. However, the Intel Nehalem architecture is very efficient with hyper-threading and allows 50-80 percent more clients. That means that when it comes to the CPU, we can host 150% * 56 = 84 VMs.

Memory

The amount of memory the host must have depends primarily on the applications the users require and the OS they use. On average a Windows XP client needs 400-500 MB of RAM for basic operations and a standard set of applications. Add some caching and the memory usage should stay below 700 MB.

The Windows OS starts paging when 75 percent of its memory is allocated. It will always try to keep at least 25 percent free. But paging in virtual environments is a performance-killer. So instead of giving it the recommended (in physical systems) amount of 1.5 to 2 times the amount of memory in swap space, we limit the pagefile size to a fixed amount of 200 to perhaps 500 MB. If that is not enough, just add more RAM to the client, rather than extending the pagefile.

This also means we aim for at least 25 percent free RAM space with most applications running. Additionally, about half of the used memory contains the same blocks in all clients (Windows DLLs, same applications, etc). This is lower on Windows 7 clients because of ASLR (Address Space Load Randomization), which means that the amount of memory shared between clients is 25% (empty space) + 75% / 2 = 62.5%.

So when running Windows XP on ESX servers, if 60 percent of memory per client is actually being used, 50 percent of which is shared between clients, we need 1 GB x 60% x 50% = 300 MB per client. Every VM needs about 5 percent more than the amount allocated as overhead from the host. So you need an additional 50 MB (5 percent of 1 GB) per client. We have seen from the CPU calculation that we can host 84 clients, so a host would need 4 GB (for the host itself) + 350 MB x 84 = at least 34 GB of RAM.

However, if 75 percent of memory is used and only a third of that can be shared, every client needs 1 GB x 75% x 67% = 512 MB of dedicated host memory. So for 84 clients the host needs 4 GB + (512 + 50) MB x 84 = 52 GB of RAM.

Of course if you run on a host that doesn’t support transparent page sharing, the amount of memory needed is 4 GB + 84 * (1024 + 50) MB = 96 GB of RAM.
For Windows 7 clients the numbers are (2 GB + 100 MB) x 60% x 50% = 660 MB per client on average, 4 GB + 660 MB x 84 = 60 GB of minimum host memory and 4 GB + 84 x (2 GB + 100 MB) = 188 GB per host if the host doesn’t support memory over-commitment.

Disks

The amount of IOPS a client produces is very much dependant on the users and their applications. But on average, the IOPS required amount to eight to ten per client in a read/write ratio of between 40/60 percent and 20/80 percent. For XP the average is closer to eight, for Windows 7 it is closer to ten, assuming the base image is optimized to do as little as possible by itself and all IOs come from the applications, not the OS.

When placing 84 clients on a host, the amount of IOPS required would be 840, of which 670 are writes and 170 are reads. To save on disk space, the disks are normally put in a RAID5 set up. But to deliver those numbers, we need 670 / 45 + 170 / 90 (see ‘RAID5’ section earlier in this document) = 17 disks per host. Whether or not this is put in a central storage system or as locally attached storage, we will still require 17 disks for 84 VMs. If we used RAID1, the number changes to 670 / 90 + 170 / 110 = 9 disks. That means, however, that using 144 GB disks, the net amount of storage drops from 17 x 144 GB x 0.8 (RAID5 overhead) = 1960 GB to 9 x 144 GB x 0.5 (RAID1 overhead) = 650 GB.

Practical Numbers

All these numbers assume that clients are well-behaved and that most of the peaks are absorbed in the large averages. But in reality you may want to add some margins to that. To be on the safe side, a more commonly used number of clients per host is 65 (about 3/4 of 84). That means that the minimum amount of memory for the average XP client solution would be 65 x 350 MB + 4 GB = 27 GB, or for Windows 7: 65 x 660 MB + 4 GB = 47 GB.

The amount of IOPS needed in these cases is 10 IOPS x 65 clients = 650 IOPS where 80 percent (= 520) are writes and 20 percent (= 130) are reads. With RAID5 that means we need (520 / 45) + (130 / 80) = 13 disks for every 65 clients. Should you require 1,000 VDI desktops, you will need (1000 / 65) x 13 = 200 disks. Put on RAID1, that number decreases to 108, which is quite substantial considering that it is still only nine clients per disk.

So, to be sure of the number you need to use, insist on running a pilot with the new environment where a set of users actually use the new environment in production. You can only accurately size your infrastructure once you see the numbers for those users, the applications they use and the IOPS they produce. Too much is dependent on correct sizing - especially in the storage part of the equation!

Summary

The table below summarizes the sizing parameters:

The following table summarizes the IOPS for the different RAID solutions:

To illustrate the above figures, a few samples follow:

Alternatives

Cache

There are many solutions out there that claim to speed up the storage by multiple factors. NetApp has its Performance Acceleration Module (PAM), Atlantis Computing has vScaler, and that’s just the tip of the iceberg. Vendors such as Citrix with its Provisioning Server and VMware with its View Composer also aid storage by single-instancing the main OS disk, making it much easier to cache it.

But in essence they are all read caches. Caching the IOPS for the 30 percent that are reads, even with an effectiveness of 60 percent, will still only cache 30% x 60% = 18% of all IOs. All write IOs still need to go to disk.

However, most storage systems also have 4 GB, 8 GB or more cache built-in. While the way it is utilised is completely different for each vendor and solution, most have a fixed percentage of the cache reserved for writes, and this write cache is generally much smaller than the read cache.

The fact is that when the number of writes remains below a certain level, most of them are handled by cache. Therefore it is fast; much faster than for reads. This cache is, however, only a temporary solution for handling the occasional write IO. If write IOs are sustained and great in number, this cache needs to constantly flush to disk, making it practically ineffective. Since, with VDI, the large part of the IOs are write IOs, we cannot assume the cache will fix the write IO problems, and we will always need the proper number of disks to handle the write IOs.

SSD

SSD disks are actually more like large memory sticks rather than disks. The advantage is that they can handle an amazing amount of IOPS; sometimes as high as 50,000 or 100,000. They have no moving parts so accessing any block of data takes mere microseconds, instead of milliseconds.

However, the current state of the SSD drives only allows every cell to be written 1,000 to 10,000 times. That means that, even with smart tricks like moving cells around to spread writes, the sustained writes of a VDI solution would break an SSD disk within a few months. This ‘spreading writes around’ is called TRIM and is the reason why writes are so much slower than reads on SSDs.

Also, the current backend of any storage solution handle the number of IOPS those drives can offer. Most vendors don’t recommend SSD drives as yet for large scale storage demands. Aside from this fact, they are also very expensive - sometimes costing four to ten times as much as 15,000 RPM SCSI disks.

It is expected that this may change soon, as better SSD cells are constantly being developed. With a more even read/write ratio, a longer lifespan, larger disks and better pricing, we may see SSD disks in a SAN become more common within a year or two.

In Conclusion

It should be obvious by now that calculating the amount of storage needed in order to properly host VDI is not to be taken lightly. The main bottleneck at the moment is the IOPS. The read/write ratio of the IOPS that we see in practice in most of the reference cases demonstrate figures of 40/60 percent, sometimes even as skewed as 10/90 percent. The fact is that they all demonstrate more writes than reads. And because writes are more costly than reads - on any storage system - the number of disks required increases accordingly, depending on the exact usage of the users and the application.

Some questions remain:

What is the impact of application virtualization on the R/W IOPS?
What exactly is the underlying cause of the huge difference in read/write ratios between lab tests and actual production environments?
What if all the write IOs only need to be written to a small part of the total dataset (such as temporary files and profile data)? Could all the data, or at least most of it, be captured in a large write cache?

These questions will be investigated as an increasing number of VDI projects are launched.

And as a final note, it is imperative that you run a pilot. Run the actual applications with actual users in the production environment beforehand so that you know how they behave and what the read/write ratio is. If you don’t size correctly, everybody will complain. All users, from IT staff to management and everybody in between, will complain and the VDI project… will FAIL

VDI and Storage = Deep Impact!

Comments or Feedback ?! Please let us know!

Credits

The credits for this information are for my colleague Herco van Brug.

The whitepaper can be downloaded from the Virtuall website as well: http://virtuall.eu/download-document/vdi-storage-deep-impact

Find Herco and Ruben on twitter: www.twitter.com/brugh and www.twitter.com/rspruijt

2010: the year of choices?!

Ruben Spruijt — Tue, 20 Oct 2009 21:27:00 GMT

The adoption of Application Virtualization, Server-hosted Virtual Desktop Infrastructure (VDI), and the availability of Microsoft Windows 7 creates a lot of interesting and useful possibilities in the area of Application and Desktop Delivery (ADD). Multiple organizations are wondering what their new ‘workspace’ should look like. End users are demanding more functionality such as flexibility, freedom, roaming, hoteling, device and platform independent access to Windows and web-architected applications. IT staff demands cost reduction, manageability, availability and compliance. Irrespective of which Application- and Desktop delivery concepts, solutions, and products you prefer, I am convinced that 2010 will be THE year of choices!

More and more organization are confused with all the ADD vendors, solutions and products. It's a booming market for sure! Maybe this overview will help you understand the Application and Desktop Delivery landscape.

With the upcoming release of Microsoft App-V 4.5 SP1 (soon!) and updates from all the AppVirt vendors on the horizon, the Application Virtualization Solutions Overview and feature comparison document will be updated as soon as possible. The document "A Complete Application Virtualization Solutions Overview and Feature Compare matrix" can be found here. Microsoft is fully aware of the powerful App-V solution they have in their portfolio. It’s a key component in optimizing the (Virtual!) desktop. The document ‘Microsoft Application Virtualization Cost Reduction’ gives a clear view of optimizing the desktop with Application Virtualization in general and App-V specific and is an article worth reading. I noticed that not so much people are aware of this document therefor the direct link here

I'm sure that Application Virtualization is key (essential!) in local and centralized Desktop Virtualization. The statement: “Without Application Virtualization no stateless Virtual Desktops” could be mine.

What do you think: Is 2010 the year of mainstream adoption of (server-hosted/client-side) Desktop Virtualization?! Is Application Virtualization a key component in Desktop Virtualization!?

BriForum 2009 Smackdown!

Ruben Spruijt — Tue, 28 Jul 2009 21:01:00 GMT

Past week was one of the most interesting weeks of the year! BriForum 2009 is the Application and Desktop delivery event with no-nonsense presentations, great presenters and cool vendors. More than 405 attendees (vendors included) where at the venue. This is really a good development when you keep in mind the economical difficult times. This signal means that Application and Desktop delivery is solid, cool and 'state-of-the art’.

One of the presenters was Ruben with a total of three different presentations. The presentations ‘Streaming Smackdown 2009’, ‘a complete application and Desktop delivery overview’ and ‘Project VRC: Performance Best Practices for Virtualizing Desktops and Terminal Services’ where well attended and awesome to give!

Together with Jeroen van de Kamp and Shawn Bass, the co-presenters in two sessions, we had really fun in informing the audience with great content and (hopefully) awesome presentations.
With the help of email and twitter I receive a lot of requests of people who are asking for the three presentations. The attendees of BriForum already have access to these presentations. The people who didn’t attend, CU in 2010 in the US and/or Europe?! For the people who doesn’t want to wait until 2010 here are the direct links to the presentations ‘Streaming Smackdown 2009’,’ a complete application and Desktop delivery overview’ and ‘Project VRC: Performance Best Practices for Virtualizing Desktops and Terminal Services’ . All the sessions are video recorded and exclusive for BriForum 2009 attendees..

In the Streaming Smackdown presentation there where three demo’s included. As a backup I recorded these demo’s and uploaded them to Youtube for 'future use' as well.

Demo #1: App-V + Win7 Standalone demo
Microsoft App-V 4.5 CU1 is running in standalone mode on Windows 7 RC x86 Operating System. The App-V applications are stored on a USB removable storage device and automatic imported with App-V Auto importer tool from Login Consultants (still Beta).
Goal: show ease of use with App-V and Win7
http://www.youtube.com/watch?v=FkSPxI-8eqE

Demo #2: Windows 7, XP mode for Windows 7, ThinApp, Legacy apps
Microsoft Windows XP is running as a Guest VM with XP mode for Windows 7. VMware ThinApp takes care of different (legacy) Windows applications that are started in the XP Virtual Machine and presented seamless on the Windows 7 Operating System.
Goal: Use legacy apps installed and virtualized on XP, seamless presented in Win7
http://www.youtube.com/watch?v=Pp_vPC1e8_A

Demo #3: Citrix Dazzle + XenDesktop + ThinApp
Citrix Receiver and Citrix Dazzle are used on a Windows 7 machine to access two different Virtual Desktops. The Vista and Windows7 Virtual Machine is access with Citrix XenDesktop. The VM’s are running on Hyper-V 2.0 and VMware vSphere. VMware ThinApp is executing Microsoft Office 2007 and Office 2010 on these desktops. After accessing the Virtual Desktops VMware ThinApp also starts Office 2010 applications on the local instance of Windows 7.
This demo is the first public demo of Windows 7 + Office 2010 with support of VMware ThinApp!! (Unique)
Goal of this demo: Make the most bizarre combination of technology solutions and bring them together for ultimate application and desktop delivery ;-) SUPER GEEK!
http://www.youtube.com/watch?v=6qqvGpSdOlQ

In the presentations I refered to two whitepapers which can be found here: 'Application Virtualization Solutions Overview and Feature Compare matrix - UPDATED' and 'Understanding all the Application and Desktop delivery solutions in 30 minutes UPDATED) I really hope that this information make sense! when you have comments or suggestions to make the content and presentations even better please let me know.

For me it was really an honor to present at BriForum, I am looking forward to meet you next time!

Application Virtualization Solutions Overview and Feature Compare matrix - UPDATED -

Ruben Spruijt — Mon, 29 Jun 2009 01:01:00 GMT

The whitepaper, Application Virtualization Solution Overview and Feature Compare matrix, will provide new and updated information about the various Application- and Desktop Delivery solutions, Application Virtualization in general and the main Application Virtualization vendors. It also includes a matrix with feature details of the different Application Virtualization solutions such as Altiris SVS, Citrix XenApp, Microsoft App-V, Vmware ThinApp, InstallFree Bridge, Endeavors Application Jukebox and Xenocode. It’s important to understand that the vision of application- and desktop delivery and the focus of the vendor is more important than only comparing the features of each solution. Despites of that, comparing features can help in finding the right application virtualization solution that fits in the business and technical requirements of your organization.

Frequently customers are wondering which Application Virtualization solution is the best? it’s impossible to give a general answer to that question. It depends on the demands of IT management, customers needs, business case and the current ICT infrastructure. This whitepaper will help in evaluating which solution fits the best in your organization. Upcoming BriForum together with other awesome presenters, Ruben will give a presentation where all these Application Virtualization solutions will be clarified. This session is called Streaming Smackdown 2009, a must see!. When you have questions, additions or remarks about this whitepaper please leave a comment on Brianmadden.com or give me a tweet

Understanding all the Application and Desktop delivery solutions in 30 minutes 2.0 (UPDATED)

Ruben Spruijt — Sat, 13 Jun 2009 20:14:00 GMT

Last year I created a blog entry "Understanding all the Application and Desktop delivery solutions in 30 minutes". Together with this blog entry a graphical diagram of all the different delivery concepts was created as well. The Application and Desktop delivery market space is rapidly evolving in many ways. I want to share the updated (v2.0) grahical illustration and explanation with you. There are many changes made in this illustration. I am sure this diagram will cover the application and desktop delivery concepts for upcoming 1-2 years.

This “Application & Desktop Delivery Solutions Overview” to provide a full at-a-glance outline of the various application and desktop delivery solutions. Reading this blog entry ent, which accompanies the Overview, will only take about 30 minutes, and will give you a complete outline of the diagram* and all the application and desktop solutions that are included in it. There are so many delivery solutions available on the market that - often due to a lack of knowledge - their functionalities are frequently mixed up. This article does not aim to describe all application scenarios or their technical advantages and disadvantages, but to give a general idea of the state of affairs in the application and desktop delivery segment, independent of vendors. I hope this overview will be of some value to you.

Trusted and Untrusted Work Place Scenarios

Trusted work places are devices that are connected to the existing IT backend infrastructure via wired or wireless LAN/WAN. Untrusted work places are devices that do not have a secure wired or wireless LAN/WAN connection to the existing IT backend infrastructure. This is, for example, equipment that is connected to a separate network segment for security reasons or because it is used from home or at a work experience location.
Each organisation has different work place and application delivery scenarios. For the IT department, it is important to have a good overview of the various work place and application delivery scenarios, since this indicates how the various users work with the applications or what their requirements are

Secure Access

Secure Access solutions provide secure access for untrusted devices to corporate IT. The two parts of the symbol stand for secure (the shield) and access (the traffic light). Depending on the chosen solution, secure access can also be fine-grained. Solutions that can be used to realise secure access scenarios include Cisco ASA, Citrix Access Gateway, Microsoft Intelligent Access Gateway, and Juniper SSL VPN.

Web Application Acceleration

Web Application Acceleration appliances accelerate and secure web-architected applications. We are all confronted with these solutions nowadays: internet applications such as Google, MSN and eBay all use them. Web application acceleration solutions are not just useful for large organisations; however, you could also use them for your own web applications. Solutions that facilitate web application acceleration and security include packages such as Citrix Netscaler en F5 BigIP.

Connection Broker

The connection broker determines which server-hosted remote desktop will be made available to the client. When using a server-hosted virtual desktop infrastructure for this, it is possible to either designate dedicated desktops or a pool of remote desktops. The desktop broker can automatically create, remove or pause remote desktops. There are a number of connection broker suppliers. Citrix with XenDesktop, Microsoft with Remote Desktop Services, and VMware with View are the best-known total solutions. Depending on the supplier, the connection broker may have additional functions, such as a web interface that can create secure (SSL) connections to remote desktops, and also Directory Services integration, Full USB support, support for various display protocols and integration with Terminal Services. Depending on the rules, it is possible to execute applications centrally on a server-hosted VDI or on a terminal server.

Application Streaming and Virtualization

Through application streaming and virtualization, Microsoft Windows applications can be used without changing the local operating system or installing application software at a particular work place. In other words; the application can be executed as if it had been installed locally and can save data and print without the need of any modifications to the local client. Resources such as the CPU, memory, hard disk and network card take care of the execution of these applications.
Application Streaming and Virtualization can make applications available to desktops, laptops, server-hosted VDIs and terminal services platforms. The applications are executed on a “client” platform, without needing to modify the platform.
The advantages of Application Virtualization include: installation, upgrade, roll-back, delivery speed and the ease of application support (management). Installation of applications is no longer necessary, eliminating the possibility of conflicts. The result is a dynamic application delivery infrastructure.
Application Streaming and Virtualization solutions include: Microsoft App-V, VMware ThinApp, InstallFree, Symantec Workspace Virtualization and Citrix XenApp client side virtualization.

OS Provisioning

OS Provisioning allows workstations to boot up and run from a central image. A single image can be used simultaneously by multiple workstations. The advantage of this is that complete operating systems, including applications and clients, can be made available quickly and securely. It is possible to make a single image available to multiple VDIs, TSs and physical desktop environments without causing conflicts. As a result, it is possible to upgrade or roll-back an OS quickly, simply, and without significant risks. When virtual desktops use OS streaming, (valuable) storage is saved, and the management of virtual desktops becomes relatively simple. This means that virtual or physical machines using OS Provisioning can become “stateless devices”. Citrix Provisioning Server and the VMware View Composer are both solutions that facilitate OS Provisioning.

Server-hosted VDI

VDI, Virtual Desktop infrastructure = Dedicated Virtual Desktop
There are two kinds of VDI: server-hosted and client-side. A Server-Hosted Virtual Desktop Infrastructure (VDI) is a dedicated remote desktop solution providing remote access to Windows XP/Vista/Win7 or Linux desktops. The virtual machines are run from the data centre. The virtual infrastructure increases the system’s independence, availability and manageability. The implementation of Server-Hosted VDIs means that desktops are no longer bound to a location or end-user appliance. Each user has his own unique, personalised, fully independent work place. Programs run and data is processed and stored on a centralised personal desktop. The information is sent to the client screen via a remote display protocol such as Microsoft RDP, Citrix ICA, Teradici/VMware “PC-over-IP” or VNC.
The protocol used for displaying the correct information depends on the operating system, bandwidth, the type of application, and the technical facilities. As with other desktop delivery solutions, VDI consist of various infrastructure components that facilitate management, load balancing, session control and secure access to virtual work stations. Microsoft, VMware, Quest and Citrix are all important suppliers within the server-hosted VDI segment.

Server-hosted VDI, GPU Acceleration

The “Graphical Processor Unit (GPU) acceleration” functionality can be added to the server-hosted VDI solution. It provides each (virtual) machine with enough graphic performance to run multimedia, 2D/3D, NextGen and Unified Communications.
Display data is presented to the client device via an optimized remote display protocol. To ensure that the end-users experience the best possible performance, the bandwidth, latency, or local (software) components have to meet extra requirements.

Terminal Services (TS)

Terminal Services (TS) = “Shared Remote Desktop”
Terminal Services is a solution for the remote access to desktops and applications that are run on a terminal server in a data centre, where every user has his or her unique terminal server session. Access to the desktop or application is not tied to a location or end-user machine, and programs are executed centrally on the terminal server. The data appears on the client screen through a remote display protocol such as Microsoft RDP or Citrix ICA. Terminal Services consists of various infrastructure components for management, load balancing, session control and support. It has the advantage that applications are made available quickly and securely, the TCO is low, and applications can be accessed irrespective of location or work place. Suppliers of terminal services include Microsoft, Citrix and Quest

Client-side VDI

VDI, Virtual Desktop infrastructure = Dedicated Virtual Desktop
There are two kinds of VDI: server-hosted and client-side. Client-side Virtual Desktop Infrastructure (VDI) is a dedicated local desktop. The virtual machines are run locally on the client device. The hypervisor ensures that each virtual machine is hardware-independent, and makes it possible to simultaneously use a number of virtual machines at the same workstation. The hypervisor plays an essential part in client-side VDI solutions. There are two kids of hypervisor: a bare-metal client hypervisor and a client-hosted hypervisor. The client-hosted hypervisor is installed on the Windows, Apple of Linux operating system as an application. The bare-metal client hypervisor is installed on top of the hardware, with the operating system installed on the hypervisor. The main differences between the hypervisors are hardware support, performance, manageability and end-user experience.
Citrix XenClient, VMware Client Virtualization, Neoclus en Virtual Computer are all bare-metal client VDI solutions. Microsoft VirtualPC en MED-V, VMware ACE and Fusion, Parallels Desktop, and Sun VirtualBox are client-hosted VDI solutions.

Client Management

Any self-respecting professional IT organisation is bound to use a Client Management solution, as it is needed to facilitate things such as OS deployment, patch management application and client deployment, asset management, service desk integration, and remote control. Examples of client management systems are Microsoft System Center Configuration Manager (SCCM), RES Wisdom, Altiris Deployment Solution, LANdesk Client Management and Novell ZENworks Configuration Management. Client Management is one half of the complete picture. The complete picture is User Environment and Client Device management.. (To be continued).

Finally

The solutions given in this overview all provide different ways of making applications and desktops available effectively and dynamically.
Which solution is best for your organisation depends on a number of variables. Each company has different requirements and different technological circumstances, and together they determine which solution is best.

Project Virtual Reality Check's VMware ESX white paper: UPDATED

Ruben Spruijt — Thu, 04 Jun 2009 13:16:00 GMT

A few months ago, Project "Virtual Reality Check" (VRC) released four whitepapers. These whitepapers cover Citrix XenServer 5.0, Microsoft Hyper-V 1.0, VMware ESX 3.5 and bare metal platforms running Windows Server 2003/2008 x86 and x64 Terminal Services and Windows XP as VDI workload.

The VMware ESX whitepaper has just been updated with AMD's Rapid Virtualization Indexing (RVI) results. The impact of AMD Nested Page Tables (RVI is AMD's implementation of NPT) is benchmarked and analyzed. The outcome of these tests do really have a interesting positive impact in the amount of users on virtualized x86 Terminal Server platform. You can read the impact in the VMware ESX v1.1 whitepaper which can be downloaded from www.virtualrealitycheck.net

During various various webcasts and presentations such as VMworld Europe, Citrix Synergy, Virtualization Congress we explain that “Project: VRC isn't finished…. it is just started! “. This week we started phase #2 of Project VRC. The highest priority in this phase is executing benchmarks using Terminal Server workloads running VMware vSphere using brand-new HP DL380G6 (Intel Xeon 5500 Nehalem) hardware. Also Windows7 as VDI platform will be tested and analyzed. Our goal (no promises) is to present and publish the results before the 22th of July when we present at BriForum. http://briforum.com/html/sessions.html#A19

------------------------------------

Welcome to “Project: Virtual Reality Check (VRC)”!
More and more people ask advice about the hardware virtualization solutions, particularly in a Terminal Server and Virtual Desktop Infrastructure context.
PQR and Login Consultants have decided to compare the various hardware virtualization platforms in relationship to the end-user performance experience using the freely available benchmarking methodology of Login Consultants, VSI. Jointly they will deliver the outcome of the investigations and benchmarks to a broader audience, as part of the joint venture “Project: Virtual Reality Check (VRC)”.
Running Terminal Server workloads on virtual hardware is generally not recommended, but recent developments give grounds to a re-evaluation of current
best practices. By bench¬marking these and the Virtual Desktop workloads on physical servers and various virtualization solutions, Project VRC will give
you valuable and most importantly unbiased experience and insights.

Understanding all data and system availability solutions in 30 minutes: IT made easy!

Ruben Spruijt — Wed, 18 Mar 2009 16:32:00 GMT

While storage solutions and virtualization can often become a goal in themselves, in respect to availability, it’s not a simple task to design a datacenter availability solution. All aspects of the datacenter influence one another. To position the products needed for datacenter solutions and to create understanding of the components, a solutions diagram was created. This diagram in no way pretends to be a complete detailed overview of every possible solution but tries to give a general overview of the methods involved.

The Data and System Availability diagram aims to give an overview of all of the components that make up the datacenter and the relations between them.

Advanced IT-Infrastructures made easy

In an advanced ICT infrastructures it's all about Users, Applications, Data and System Availability.

Infrastructures are built to provide users with the applications they need to do their work. These applications produce data and data is provisioned by systems. To allow users to work anywhere at any time, the applications and the desktops they work on have to be delivered to them in a certain way. To give an overview of the possible ways to do that, a diagram was created called ‘Application and Desktop Delivery’ solutions. The components used in this diagram are things like Virtual Desktop Infrastructure, Terminal Server, Bladed Workstations, Application Virtualization and many more.

An advanced ICT infrastructure made easy: "Application and Desktop Delivery" and "Data and System Availability" is key!

Data and System Availability solutions overview

The dynamics of applications and desktops are making them location, device and time independent. Data and systems have completely different availability requirements. They are typically stored in a datacenter that is not dynamically provisioned, although we may see that change in the near future with the upcoming cloud computing initiatives.

(A High Quality version of the diagram can be downloaded here)

Servers

It’s servers that provide users or applications with the services they need. Services can be anything: web services, file and print services, authentication, database services, etc. In a traditional datacenter, these services are mostly executed on physical servers.

These physical servers come with a lot of resources that most services don’t need. They either have way too much storage, CPU power and memory, or too little. When there’s not enough resources available, adding more usually adds too much of the resource, over-dimensioning them.

Also, physical servers with local storage have a few disadvantages that limit their availability. If a physical server fails, the service is no longer available. A new server has to be setup, data restored and settings reconfigured. All in all a process that could take up to several days.

Storage

To cope with these availability problems, it makes sense to start with centralizing the storage. This makes it easier to allocate the right amount of storage to a service and makes it easier for the service to access it from another location, thus enhancing its availability.

Centralizing storage also has some disadvantages. All storage is now on one system that becomes a new single point of failure. If it fails, the whole infrastructure fails.

So this central storage has to be redundant in every aspect. It needs redundant connections, redundant switches, redundant power, redundant hard disks, redundant everything. This is what makes a Storage Area Network (SAN) more expensive than local storage.

Storage Area Network

Connectivity to the SAN can be divided into two main groups: Fiber Channel (FC) and Ethernet. Where Fiber Channel provides the best performance, it’s also the most expensive. A very valid question in designing a storage infrastructure therefore is ‘does the customer really need that high end performance?’. The alternatives aren’t really that far behind anymore.

Ethernet based infrastructures are less expensive because connectivity takes place over regular Ethernet switches and regular Network Interface Cards (NICs).

Not too long ago, iSCSI was the main storage protocol to be used over Ethernet. It allows LUNs to be presented as full disks to a host. With the upcoming virtualization technology however, NAS is a strong contestant now too. Whether it’s NFS or CIFS, a host simply connects to a network share and stores it’s data on the file system that the storage provides. This flexibility has some disadvantages though. Hosts are no longer managing the storage and proprietary file systems like VMFS don’t work on it. On the other hand, a storage solution with a smart file system like NetApp’s Write Anywhere File Layout (WAFL) makes it very easy, with the right toolset, to work with (consistent!) snapshots.

Thin Provisioning

With a SAN, data per gigabyte is more expensive than with local storage. The advantages of having it available independent of the servers make up for a lot of the cost but it’s still better to be conservative with allocating storage. Application developers or server administrators tend to ask for more storage than they actually need.

One solution to this problem is to give them the storage they need, but only actually store what they really use. This is called ‘thin provisioning’. It’s a smart way to dynamically size the LUN on the array as it’s needed.

Linked Clones

Another way to save storage is to use linked clones. The principle of this technique is that it provides one set of data to multiple virtual machines, while keeping track of the differences between them and storing those differences in a separate location. When this is done on the array, the performance impact is negligible.

A physical server can also provide virtual machines with linked clone disks. This is a little bit slower and does take some CPU resources away from the VMs but it doesn’t need an intelligent storage array and is also a very good solution

Deduplication

At the moment, deduplication is mainly used in backup scenario’s. That means that data is first stored on a main storage system and at backup time deduplicated at a separate system or a different tier in the storage system. The reason it is not used on active data yet is mainly because the deduplication process is a very calculation intensive process that, at the moment, simply isn’t fast enough for modern storage demands.

The deduplication process works by first accepting all data. It then either inline or in a background process, first compresses it and then at a block level, checks if that block already exists. If it does, it simply points to that block, if not, the new block is stored. This can reduce the backup data size of multiple backups by 50% to even 90% of a traditional backup data set.

Archiving

Because a central high performance storage system can be quite expensive, a lot of companies decide to move less used data to less expensive high capacity storage. This is typically done by setting up the storage in multiple tiers.

This process can be all inline of the storage system that moves data on block level to a slower, and therefore less expensive set of disks. When the data is accessed again, it is moved back to the fast storage tier. Clients and applications can access all the data as it stays online at all times.

Another way to archive data is to have a data management solution decide what data to move. This is then done at a file-, mail- or database object level. The advantage of this system is that it actually moves data out of the systems, possibly leaving a so called ‘stub’ behind as a reference for clients and applications. This means that when the data is accessed again, it needs to be restored from another location which can be a time consuming process. On the other hand, this significantly reduces the active data size which in turn reduces backup time by large factors.

Indexing service

When data is moved between different storage tiers or systems, clients, applications and backup systems can get confused about where the data is actually stored.
An indexing server keeps track of the location of all the data in a storage system. It interfaces with the archiving solution and provides a transparent interface to clients and applications. The archiving solution on demand moves data back to other tiers.

Virtualization

Once the availability of data is improved, it’s time to do the same for the servers. Having data online is only half the solution. Without services to deliver it to the clients and applications, it is of no more use than a backup.

A physical solution to improve server availability is clustering. Clustered systems require shared storage or have their own copy of the data that is kept in sync by using application level replication.

Another solution to improving server availability is virtualization. Virtual machines are independent of the physical hardware and can very easily be moved from one host to another, whether this host is on the same site or a failover site. Higher server availability can be achieved by a virtualization solution that actively monitors all virtual machines and in case of a physical host failure, automatically restarts the virtual machine on another host. Depending on the management tools available, it’s also possible to load balance all virtual machines across the available physical hosts by implementing live migration options.

There are two main types of hypervisors for virtualization solutions; the thin hypervisor, also called microkernelized hypervisor and the thick hypervisor, also called monolithic hypervisor. Thin hypervisors are used by virtualization solutions like XenServer and Hyper-V whiles ESX uses a thick hypervisor.

The complete whitepaper can be downloaded here

Credits are also for Herco van Brug (hbr@pqr.nl), we developed the Data and System Availability diagram and the whitepaper together.

Virtualization: a Beginner's Guide - New Book

Ruben Spruijt — Sat, 07 Mar 2009 06:00:00 GMT

Virtualization: a Beginner's Guide, is a new book released February 2009.

I know how much it can take to write a book on my own, and today this doesn't fit in my business and private schedule. Working together with Chris Wolf and Duncan Epping, I started tech-editing the book Virtualization, a Beginner's Guide. Danielle and Nelson Ruest spend a lot of time in writing this great book. It's not written for advanced virtualization admins but is useful for anyone new in virtualization. The latest technologies from Citrix, Microsoft, VMware are explained as well as server consolidation, application virtualization and virtual desktop infrastructures are covered. You can view chapter one and six, read the table of contents or buy the book here

People who want to update and broaden their skills in the virtualization arena should read this book. (Although I'm biased!)

Project VRC at VMworld Europe 2009

Ruben Spruijt — Sat, 07 Mar 2009 05:22:00 GMT

This past February 24-26th, I was at VMworld Europe 2009 in Cannes, France.

Our Project Virtual Reality Check presentation was really great and with 200 people in the audience, during lunch, a good session. Our presentation contained:

Test platform and methodology
Baremetal results
VMware ESX results
Future plans

You can download the presentation here. During VMworld, Jessica and Jeremy recorded some great videos. Our interview can be viewed here. For Jeroen van de Kamp and I it was really an honor to present at VMworld. PQR, the company I work for, won the European VMware Authorized Consultancy Partner of the year, awesome.

With al the great content, interesting people, nice conversations and weather it was an awesome event.

Head-to-head performance analysis of App-V, SVS, ThinApp and XenApp

Ruben Spruijt — Fri, 06 Feb 2009 02:41:00 GMT

XPnet created a whitepaper which analyze and describes the performance characteristics of Altiris SVS Pro, Citrix XenApp, Microsoft App-V and VMware ThinApp. Although the tested application set is limited it still gives a nice view of the performance characteristics of different Application Virtualization solutions.

VMWare commission the study, but did not aid or influence the results. VMWare chose Xpnet to study AppVirt performance because they developed Clarity Suite which is a fairly well known Office benchmarking application and because it’s freely available anyone can reproduce their results. This is the first real whitepaper which investigates the performance impact of various Application Virtualization solutions. My personal feeling is that there are more real independent tests to come..

The complete test report can be downloaded here

VDI and TS performance on ESX, Hyper-V, Xen, and bare-metal: head-to-head results are here via Project Virtual Reality Check!

Ruben Spruijt — Sun, 25 Jan 2009 14:01:00 GMT

Jeroen van de Kamp and I are proud to finally announce the official launch of project "Virtual Reality Check” (VRC). This is a independent research joint venture between our companies--Login Consultants and PQR. The primary purpose of VRC is to release multiple whitepapers to provide information about the scalability and best practices of virtualized Terminal Server and desktop workloads. The first phase of Project VRC compares the performance of virtualizing Windows XP and 32-bit Windows 2003 Terminal Services on ESX, XenServer, Hyper-v, and bare-metal hardware.

The four resulting white papers can be downloaded for free from www.virtualrealitycheck.net. (free registration required)

The goal of Project VRC is to investigate, validate, and find answers to the following questions:

How do various Microsoft Windows Client OSes scale when used for virtual desktops?
How does a VDI infrastructure scale in comparison to (virtualized) Terminal Server?
Which performance optimization on the host and guest virtualization level can be configured, and what is the impact of these settings on user density?
With the introduction of the latest hypervisor technologies, can we now recommend running large-scale Terminal Server or Citrix workloads on a virtualization platform?
What is the performance impact of adding Citrix XenApp to Terminal Server?
How do x86 (32-bit) and x64 TS platforms compare in scalability on bare metal and virtualized environments?
What is the best way to partition (memory and vCPU) the Virtual Machines and the hypervisor host to achieve the highest possible user density?

All together, we've carried out over 150 tests! That said, project VRC is not finished, and probably never will be.

Additional publications are planned about virtualizing x64 workloads and the other (Vista and Windows 7) client OSes. We're also looking forward to evaluating new innovations in the hypervisor (ESX v4.0, XenServer 5.1, Hyper-V 2.0, etc. ) and hardware arenas.

Keep a close look on BrianMadden.com for news about when additional white papers will be released,.

Citrix Xen-based client hypervisor video

Ruben Spruijt — Sat, 24 Jan 2009 03:38:00 GMT

A few days ago Brian wrote about Citrix 'Project Independence', a very (very) interesting and useful desktop delivery solution. In my opinion client-side bare metal hypervisors will change the way we delivery applications and desktops to users where applications are executed locally. This is awesome, in the near future we don't need Client-Management solution anymore ...!? ;-)

Gus Pinto posted a video where the Citrix Xen-based client hypervisor is running on a HP Intel Centrino laptop.

I can't wait to get my hands on this technology... what are your thoughts with this technology!?