Kirx' Blog

ProcjectVRC Whitepaper: Impact of Application Virtualization on VDI Performance

It has been a question “ever since”:

What is the perfomance impact of Application Virtualization?

Now, Project Virtual Reality Check (http://www.projectvrc.com) has released a Whitepaper that provides an idea of that. ProjectVRC compared Microsoft App-V, VMware ThinApp and Citrix XenApp Streaming running in Virtual Windows 7 machines.

While the impact is significant, there are some things to note…

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Microsoft Application Virtualization 4.6 Read Only Cache for VDI Environments #3

Assigning the updated Cache to VDI Machines

Article Series Content

#1 Introduction and Key Findings

#2 Setting up the Staging Client and Loading Applications into the Staging Cache

#3 Assigning the updated Cache to VDI Virtual Machines (this article)

The right Location for the Shared Cache

The asumption of a VDI scenario was the most important driver for Microsoft to develop App-V’s “Read-Only-Cache” functionalities. As Justin Zarb illustrated in one of his articles, storage space may become a significant cost driver in a VDI environment. Given that situation, there are some possibilities how to achieve storage savings. Please be aware that this blog article can not cover all the advantages, disadvantages and a deep technological assessment, so Iam a little bit short here: (more…)

Microsoft Application Virtualization 4.6 Read Only Cache for VDI environments #2

Setting up the Staging Client and Loading Applications into the Staging Cache

Article Series Content

#1 Introduction and Key Findings

#2 Setting up the Staging Client and Loading Applications into the Staging Cache (this article)

#3 Assigning the updated Cache to VDI Virtual Machines

Introduction

This article will focus on preparing the “Staging Client”

In App-V’s “VDI Mode”, the shared cache file potentially will be accessed permanently by different VDI machines. Therefor, any update to that Read Only Cache, including its first filling, has to be applied to a different cache file. This special instance of an App-V Cache file will be called “Staging Cache File” hereby. Because that file uses a proprietary format, the only way to apply any updates is by using a “normal” App-V Client machine. This (virtual) client machine is usually called “Staging Client”.

It is supposed that you already have a “full” App-V Infrastructure including the App-V Management Server. Also it is supposed that this infrastructure has been validated to work propperly (i.e. applications already have been deployed to Test Clients)

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Microsoft Application Virtualization 4.6 Read Only Cache for VDI environments #1

Introduction and Key Findings

This is the first article of a series discussing Microsoft App-V’s Read Only Cache

Article Series Content

#1 Introduction and Key Findings (this article)

#2 Setting up the Staging Client and Loading Applications into the Staging Cache

#3 Assigning the updated Cache to VDI Virtual Machines

Introduction

With App-V version 4.6, Microsoft introduced the ability to configure its Client’s Virtual Application Cache (= “Cache”) to be accessed in Read Only Mode (also referred to as “ReadOnlyFSD”).

The App-V Cache is a potentially large file (up to 1 TB max) that contains copies of the application packages (“SFTs”) in order to allow fast (local) access to resources that originally are stored centrally on the network. Due to its purpose, it was designed to reside locally on the App-V Client machine (i.e. a Windows Workstation or a Remote Desktop Server/Terminal Server). Storing the App-V Cache locally on the Client allowed the applications to launch with only a minimum impact to the performance. Because of that “local” design and the requirement to fill (load) new application packages into the Cache, full modification and exclusive access rights had to be given to the Cache File for the App-V core services and drivers in the past.

For VDI environments with hundreds or thousands of Clients, this local and exclusive approach represents a significant cost driver, because in VDI environments usually there aren’t cheap, locally attached Hard Disks installed. Instead, SAN storage has to be bought (or rented) to host the Virtual Machines operating system and applications. Because of the exclusive access approach, each VDI Virtual Machine had to have its own, dedicated App-V Cache, often 4-12 GB in size – although all of these individual cache files potentially contain the same or similar applications.

By introducing the ability to access a shared cache in Read Only Mode, Microsoft allows significant savings related to storage costs compared to old versions of SoftGrid/App-V as well as to other Application Virtualization Solutions. Additionally, it allows to store the App-V Cache file outside the VDI Virtual Hard drive, thus unlinking it from the (virtualized) operating system. This results in an increased flexibility, because changes to the Virtual Application set do not require to modify the VM image any longer.

Because of these potential advantages, the announcement of that Shared Cache approach created certain noise in the App-V community, including some hints of how to create a Shared Cache and fill it with a set of applications.

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