cached exchange mode in a remote desktop session host environment - planning considerations

8/6/2019 Cached Exchange Mode in a Remote Desktop Session Host Environment - Planning Considerations

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Cached Exchange Mode in aRemote Desktop Session Host

environment: planningconsiderations

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Cached Exchange Mode in a Remote Desktop Server Environment August 2010

Contents


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Introduction................................................................................................................1


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Storage footprint........................................................................................................1


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Performance impact...................................................................................................2


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Networked storage.....................................................................................................2


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Conclusion..................................................................................................................3


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Conclusion


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IntroductionThis document is provided as an addendum to the documentR emote D esktop

S ession H ost Capacity Planning in Windows

Server 2008 R2(http://go.microsoft.com/fwlink/?LinkId=196861) and is provided sothat you can accurately evaluate Outlook Cached Exchange Mode when you prepare

to deploy Microsoft Office 2010 in your Remote Desktop Session Host (RDSH)

environment. The Remote Desktop Session Host Capacity Planning in Windows

Server 2008 R2document should be the starting point for any analysis of anRDSH

deployment.We generated the disk and network I/O statistics that are shown in this

document by using the same environment and test procedure that is described in

the Knowledge Worker v2 scenario in the Remote Desktop Session Host Capacity

Planning in Windows Server 2008 R2 (http://go.microsoft.com/fwlink/?

LinkId=196861) article.

Historically,Microsoft Outlook has only been supported in anRDSH environmentwhen it is deployed in Online Mode and connected to a Microsoft Exchange

Server.This is still the recommended configuration for Microsoft Outlook 2010 when

it is deployed in an RDSH environment. However, customers who deploy

Outlook 2010 now have the supported option of enabling Cached Exchange Mode

when Outlook 2010 is installed in a Remote Desktop environment.Cached Exchange

Mode might be ideal for deployments in which Outlook is connecting over a high

latency connection to an Exchange server that is located remotely. For the

relatively few users who access Outlook through a remote desktop, this might be

the ideal configuration. However, Online Mode against the Exchange server is still

the most scalable and optimized configuration for large deployments.

This white paper coversthree major areas that you should consider when you deploy

Outlook 2010with Cached Exchange Mode in a Remote Desktop environment:

Storage footprint

Performance impact

Networked Storage

Storage footprint

In Cached Exchange Mode, Outlook stores a local copy of each Exchange mailboxand address book on disk.Since no data is stored locally in Online Mode, Cached

Exchange Mode increases the storage that is required for an Outlook 2010

deployment proportionally to the size of each deployed Exchange mailbox.The

following example demonstrates that increase.

Exchange mailbox +

Outlook Address

Local Disk Footprint

(Cached Exchange

Local Disk Footprint

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Booksize Mode) (Online Mode)

~500MB ~1 GB or more ~0 MB

Performance impactDue to the changes in disk and network load, deploying Outlook 2010 in Cached

Exchange Mode impacts the number of users who can be supported on a single

RDSH instance.

Using the same test that is described in the document Remote Desktop Session

Host Capacity Planning in Windows Server 2008 R2 (http://go.microsoft.com/fwlink/?

LinkId=196861) for Knowledge Worker v2, we measured the disk and network I/O

characteristics in an RDSH environment.The following chart describes the disk I/O

behavior of Outlook 2010 in Cached Exchange Mode.

We took this measurement after the initial mailbox sync was completed. It is the

Outlook 2010 behavior in steady state usage. Expect I/O loads to be heavier

during the initial mailbox sync. Because Online Mode does not store a local copy of

the mailbox, there is essentially no steady state disk I/O in that configuration.

Networked storageIn many RDSH and Virtual Desktop Interface (VDI) environments, disk storage is

located on a separate networked location from the primary server.This is

advantageous in Pooled VDI infrastructures, because it does not require a rebuild of

the Outlook data file (.ost) each time the user logs in from a new endpoint.

With Outlook 2010 in Cached Exchange Mode, the data store is accessed over the

network rather thanfrom a local hard disk.This scenario is only designed for

networks that have high bandwidth and high levels of reliability.Keep in mind that

this scenario causes all Outlook Disk I/O to be directed over the network.

The following chart shows the differences in network I/O load, based on the storage

location.The red line represents the total load when the .ost file is placed on a

remote location (SMB network share).Network load increases substantially when

storage is located in a remote location.In our specific test, the average networkload increased by a factor of approximately 10, when compared to a locally

stored .ost file.This scenario is only recommended in configurations that can sustain

this I/O load. Otherwise, users Outlook user experience might be degraded.We

strongly advise that you test this configuration in a test environment that closely

mirrors your deployed environment so you can validate that Outlook client

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performance and user experience remain acceptable, evenwith the elevated

network loads.

ConclusionThe information in this document, and the information that is contained in the

overall RDSH scalability documentationshould provide you a good starting point to

evaluate and test Outlook 2010 with Cached Exchange Mode in anRDSH

environment.As with any new configuration, it is important that a deployment in this

configuration be dependent on extensive testing in a test environment that closely

mirrors yourreal-world environment.


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