How to manage CAS Performance?

The Client Access Server (CAS) is dedicated to user connectivity in the Exchange environment, ensuring mailbox access through various protocols. The health of this critical bridge depends on multiple services that GSX constantly checks for you.

GSX Monitor & Analyzer main features

Managing the service delivered by the Client Access Server

Manage the performance of your end users connections

Capacity planning on Client Access Server availability and usage

Managing the Offline Address Book

Managing the automatic configuration of Exchange Users

GSX tests the performance of the service provided by the CAS through multiple built-in Synthetic transactions that simulate user connection to their mailbox. Be aware of performance problems, identify bottlenecks and follow your capacity in real time!


Managing the service delivered by the Client Access Server

How to manage the service without managing the performance delivered to the user?

GSX Monitor includes several built-in tests that check the quality of the service provided to the end user and collect performance statistics that you can easily trend and compare across your multiple CAS to troubleshoot problems and detects bottleneck in your infrastructure, all in one click, without installing any code on the servers.

To test the availability and the performance of your CAS protocols from a user perspective, GSX Monitor provides connectivity checks and latency alerts that simulate actual CAS use by accessing any mailbox, listing the mails available, and opening the first one it finds.

When 99% of the monitoring tools force you to test the Exchange test mailbox, GSX allows you to choose the mailbox you want in order to test different type of population. You can now test the latency for VIP databases for example being alerted of performance slow down, before your user. Remove all your VIP users complains, be aware of performance problem before them!

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Manage the performance of your end user connections

Clients can connect to their mailbox through the CAS via multiple ways.
Via their Outlook client through Outlook Anywhere, via other client that support IMAP and POP3, via a Web Browser through OWA or even via their Mobile Phone through ActiveSync.
To measure the service delivered by the CAS to your end user, you need to test each of these features, constantly, performing end user scenarios and retrieving the performance for trending purposes, troubleshoot or bottlenecks analysis.

IMAP and POP3 end user performance test

GSX Monitor makes a PowerShell test to simulate an end user connection and synchronization from a POP3 or IMAP client to the CAS server until the mailbox.
GSX allows administrator to set up threshold in order to have a full control on the performance delivered by the CAS server, being alerted in case of any decrease. Moreover all the performance data will be available in GSX Analyzer for trends, forecast and comparison across the entire infrastructure.

Outlook Web Access end user performance test

This test places GSX as a user who would like to access its mailbox through any browser via OWA. It checks that Microsoft Office Outlook Web App is perfectly running and then retrieves the performance seen by a user trying to connect himself to the Web application. This test also checks the connectivity of Outlook Web App for all Microsoft Exchange Server 2010 virtual directories on the chosen CAS and for all the Exchange mailboxes that are in the same Active Directory.
As usual, GSX doesn’t only test the availability; it tests the performance of the service allowing you to set up threshold and be alerted in case of any decrease of performance.

Moreover, because this remote connection is so critical, GSX gives you the ability to also be alerted when the OWA average response time exceed a predefined threshold. The alert and the statistic are available in GSX Analyzer for trends, forecasts and comparison across your entire infrastructure.

ActiveSync end user performance test

Because more and more of your users connect their mobile devices with Exchange via Activesync, because they received mails and work with these devices, the availability and the performance of the synchronization between devices and Exchange servers becomes fundamental.
GSX proceeds to an end user test of synchronization, acting as a mobile device trying to make a full synchronization and test the Direct Push with its mailbox. You can make this test on the Extest mailbox or any other mailbox from your Client Access Server. The test just requires one click to be enabled or disabled.
This test proceeds to a synchronization step by step.

  • GSX first makes a request as a mobile could make it to check the protocol version.
  • Right after he tries a folder synchronization to retrieve all the folder hierarchy of the mailbox. 
  • Then GSX initiates the synchronization and creates a communication channel with the mailbox in order to retrieve the number and size estimation of items (mail, calendar, note, contact) waiting for synchronization. 
  • GSX then synchronizes all existing data in the test folder.
  • Then comes the Direct Push test. For that, GSX checks if the mobile is able to receive a push notification doing a real notification ping on the virtual device.
  • Finally, GSX takes one complete item of the list and makes a complete download and synchronization of it to finish its test.

All these tests are built-in features, available in one click, that measure the availability and the performance of all these ActiveSync services.
As always with GSX, you can make these tests from every Client Access Server, compare the results in GSX Analyzer or check real time performance with the GSX Monitor graphs.
End user ActiveSync Performance is now under control and you can be alerted as soon as the performance threshold you defined is exceeded. It’ll prevent any user impacts.

Outlook Anywhere (former RPC/HTTP)

This protocol is one of the most widely used because it enables the communication between the outlook client and the Client Access Server:

  • Each time an Outlook client is used, this protocol is used
  • You can be in the company, at home or on any public Wifi, it is always this protocol that is used
  • It reflects the performance experience by 90% of the users of the company

GSX tests the availability and the performance of this protocol through different tests.
The first one is the PowerShell connectivity latency test that makes an end-to-end user test that verifies simultaneously:

  • The Autodiscovery connectivity
  • The creation of a user profile
  • The logging onto the user’s primary mailbox or archive mailbox

This test uses the Exchange architecture for a complete connection to the mailbox. Once again, GSX gives you a real time view on the performance experienced by your users, alerting you before it impacts them if the performance is decreasing!

The second test deals directly with the Autodiscover service as it checks if the Outlook Anywhere configuration is able to be retrieved directly by the Exchange server.

Finally, GSX gives you an insight on RPC Client Access User Count. Because this protocol is mainly used within any Exchange infrastructure, you need to know in real time the number of users accessing the server with the RPC protocol. GSX automatically displays it to give you control on the Client Access Server load.

Capacity Planning on Client Access Server availability and usage

Reporting on CAS availability and usage can be a nightmare without GSX. Performing PowerShell test manually every minute to collect availability statistics and store them into a database where you could trend and forecast in one click on the critical statistics you need is just a dream.
This is what GSX does for you, out of the box, without any code on server.

CAS role availability: GSX calculates this statistics comparing the results of each protocol to determine the health of the service provided by the CAS. It allows you to directly check which CAS in your infrastructure experience user performance problem. Combined with usage statistics, it allows you to identify and repair any capacity problem within your infrastructure.

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Protocol availability: For each CAS, GSX trends and forecasts end user protocol performance statistics to help you define the best balance between your servers.

CAS Usage statistics: Quite often, capacity problems come from a wrong split of the number of users among your CAS infrastructure. GSX automatically trends and forecasts the user activity on your CAS, calculating the average and the peak of charge to see how the sizing of the Infrastructure supports its real usage. For example, if the sizing was for 500 concurrent connections, and the number of connections often exceeds 700, this can lead to latency.

System Server Statistics: Because system information is also very helpful, GSX does not forget them. You can choose to add any CPU, RAM, Exchange server availability, network in your report!

Managing the Offline Address Book

The Offline Address Book is a central feature for any Exchange user. Synchronization is fundamental for everybody to have the same Address Book on the Outlook client.
To manage that, GSX performs several tests.

Threshold on download task queued: What if your users can not synchronize their Address Book with the Offline Address Book? It can lead to serious problem for them. To avoid that, GSX alerts if the threshold on the number of Outlook client waiting for replication is exceeded. That gives you perfect control on this critical synchronization.

Test of the Outlook Web Service OAB: This test checks if it is possible for a user to get the good configuration parameter to access to the OAB Web Service.  It gives critical information in case of failure to troubleshoot any problem.

Status of the FDS-OAB: Queued and Completed

  • Queued: The download task queue can back up when multiple clients ask for a copy at the same time, especially when everybody open their mailbox. If this counter explodes, the server can have a performance problem or fail to spread the OAB.
  • Completed: The number of users who have downloaded the OAB successfully.

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Managing the automatic configuration of Exchange Users

The Autodiscover is a central point in the CAS infrastructure. It automatically configures user profile settings for Outlook client and provides access to Exchange features. Hence checking constantly if health is critical.
GSX performs several PowerShell tests to measure the availability and the performance of the Autodiscover service and gives the results in a comprehensive toolbox to help you troubleshoot any problem.

GSX tries to retrieve the configuration parameter of a test mailbox for multiple services:

  • Availability Service: free busy calendar service
  • Offline Address Book: used to synchronize remote client
  • Outlook Anywhere (former RPC/HTTP): the way to connect to your Exchange server through your remote exchange client
  • Unified Messaging: to check if everything is well configured to access this key service.

Each check is detailed in the statistic view giving the detail of the performance of each element in real time!