Distribution of User Load

[This topic is intended to address a specific issue called out by the Exchange Server Analyzer Tool. You should apply it only to systems that have had the Exchange Server Analyzer Tool run against them and are experiencing that specific issue. The Exchange Server Analyzer Tool, available as a free download, remotely collects configuration data from each server in the topology and automatically analyzes the data. The resulting report details important configuration issues, potential problems, and nondefault product settings. By following these recommendations, you can achieve better performance, scalability, reliability, and uptime. For more information about the tool or to download the latest versions, see "Microsoft Exchange Analyzers" at http://go.microsoft.com/fwlink/?linkid=34707.]  

Topic Last Modified: 2006-09-06

The Microsoft® Exchange Server Analyzer Tool has determined that your server has a high RPC operations-per-second count.

If your server has a high RPC operations-per-second count, you can use the Exchange Server User Monitor (ExMon) to identify how the load is distributed. It is important to determine if the load is caused by one of the following circumstances:

  • There is a relatively small number of active users.

  • The load is distributed across many users.

If a single user is identified as causing a high percentage of the load, the Exchange Server Analyzer displays a warning stating that high usage can be traced back to a single user. If this is not the case, the Exchange Server Analyzer displays a message stating that the load is distributed across many users.


RPC traffic changes over time. Therefore, to capture statistically relevant data about how users use Exchange, you may need to collect data multiple times.

Additionally, it is typical that some common user operations will expend large amounts of CPU utilization for a short period of time. Do not be concerned about this activity unless the same user is expending large amounts of CPU utilization frequently or over long periods of time.


You can safely disregard this warning if the source of the high load is a known service or process that is expected to have high load and which processes requests for many users and generates a higher load than individual users. Some services that sync mobile devices, server processes that manage free busy, services related to voice mail or unified messaging, and server processes that move users are examples of services or processes that can cause higher load than individual users.

To correct this problem

  • If the RPC rate is high (for a single user or for everyone), find out if users have desktop search engines, third-party client plug-ins, or mobile devices that synchronize e-mail with the user’s mailbox. For more information about troubleshooting third-party applications, see Turn Off Third-Party Add-ins on Client.

  • Users should have fewer than 5,000 items in the default and heavily used folders.

  • As a best practice, mailboxes should be 1 GB or less in size. For users who are causing the high load, it is recommended that they archive their mailbox items to a .pst file. Then you can run the Exchange Performance (Perfmon) tool again to see if the user is continually causing high load.

  • Contact the user to identify client applications that may be accessing the client e-mail program. Remove these applications and then reinstall them one at a time to observe their impact on the server.

  • False-positives are common when troubleshooting user load. Therefore, it is recommended that you run ExMon again during a time of high load to see if the analysis is consistent.

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