GSX Blog

Exchange Capacity Management

Posted by Carl Drechsel on Thu, Mar 29, 2012

Exchange 2010

Ensuring that your Exchange 2010 environment continues to operate at peak performance requires administrators to keep a constant eye on the growth and evolution of their user population, data storage and client access. These efforts can be time consuming but will ultimately ensure the long term performance of the systems in their charge. Properly monitoring your environments capacity allows administrators to plan for its growth. This information is critical when determining what additional servers or disk space is needed and also justifying their expenses.

When it comes to the ongoing monitoring of your environments capacity it is crucial to measure and trend the following: 

  • User Population & Message Traffic
  • Server Performance

Obviously a lot goes into overall capacity planning, including disk design, network performance and site design.  In this post we’re going to talk about the ongoing management of your environment and planning for increased capacity.

User Population & Message Traffic

One of the key things to take into consideration for projecting capacity for an Exchange environment is the number of mailboxes the environment hosts. The more mailboxes hosted places more demand on client access, hub transport and your mailbox backend.  As such a constant increase in user mailboxes and increased message delivery will eventually bring the need additional infrastructure to support the growth.

Most Exchange environments plan for a fixed maximum number of users per server per database according to a certain conglomeration of user profiles. As your environment evolves user profiles change and upsetting the original architecture. We can easily place a limit on the size of a user’s mailbox however the usage profile is not something easily limited.  Changes in user patterns can put additional stress on your backend storage as well as client accessibility.

Server Performance

As reviewed in my previous post regarding Client Access Server monitoring there are a few server level hardware performance statistics to take into consideration. These include processor and memory utilization as well as network saturation. These can be monitored by using standard windows Performance Monitor counters for the associated hardware components.  See below for a few examples to keep an eye on.



Processor (_Total)\% Processor Time

The average percentage of time that all processors are active. This counter is the primary indicator of average processor activity. This value is derived by calculating the percentage of time during the sample interval that all processors spent in executing their idle thread (which consumes cycles on a processor when no other threads are ready to run), and then subtracting the result from 100 percent.


This value should remain below 75%, if you’re constantly running above that the server is over utilized, check user load as you might need to add additional servers to the CAS array

System\Processor Queue Length

The number of threads in the processor queue. Shows ready threads only, not threads that are running. Even multiprocessor computers have a single queue for processor time; thus, for multiprocessors, you need to divide this value by the number of processors servicing the workload. A sustained processor queue of less than two threads per processor is normally acceptable, depending upon the workload.

Memory \ %Committed Bytes in Use

% Committed Bytes In Use is the ratio of Memory \ Committed Bytes to the Memory \ Commit Limit. Committed memory is the physical memory in use for which space has been reserved in the paging file should it need to be written to disk. The commit limit is determined by the size of the paging file.  If the paging file is enlarged, the commit limit increases, and the ratio is reduced). This counter displays the current percentage value only; it is not an average.

Network Interface\Bytes Total/sec.

This will tell you overall how much information is going in and out of the interface. Typically, you can use this to get a general feel, but will want to look at the Bytes Sent/sec and the Bytes Received/sec for a more exact detail of the type of traffic.

Managing your environments capacity requires the ability to trend and report on these critical factors. Only by trending and reporting user population and message traffic with server and environmental performance can you truly be able to forecast and plan for future growth.  

Also if you’d like more information regarding Monitoring Exchange 2010 and how GSX can help in this area, please follow this link.


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Tags: Exchange 2010, capacity management, Exchange 2010 monitoring