Transport IsMemberOfResolver ExpandedGroups Cache nearing capacity - Yellow(>66)

Details

Explanation

This event indicates that the affected Hub Transport server may experience a performance issue. This alert is generated by an hourly check that determines the available cache space for distribution group membership.

In Microsoft Exchange Server 2010, the processing of Inbox rules and other transport rules is performed on the Hub Transport server. To process rules that contain conditions, Exchange must perform LDAP queries to evaluate distribution group membership. Because many LDAP queries could affect performance on a Hub Transport server, the Exchange code that retrieves distribution group membership is optimized to cache the distribution group information that is used for processing Inbox and transport rules. Exchange uses this cache during the evaluation of any rule that contains the isMemberOf condition. The information that is cached is made up of the following parts:

• The resolved group name

• The expanded membership list

This information is retrieved from the cache during the processing of transport rules or of Inbox rules to determine whether a recipient is a member of the particular group. The distribution group cache (isMemberof) is stored only in memory and is not written to a file on the server that is running Exchange.

Distribution group cache settings are managed by using the EdgeTransport.exe.config file. By default, this file is located in the following directory: C:\Program Files\Microsoft\Exchange Server\v14\Bin

If the available cache nears its capacity, Exchange may be unable to cache group membership. If this occurs, Exchange performs more LDAP lookups during rule processing. This may cause a performance issue on the transport server.

User Action

To resolve this problem, do one or more of the following:

• Review the Application log and System log on your Exchange 2010 servers for related events. For example, events that occur immediately before and after this event may provide more information about the root cause of this error.

• Review Operations Manager for detailed information about the cause of this problem. For more information, see the "Introduction" section in this article.

• Check the following performance counter by using Microsoft Reliability and Performance Monitor:

  • Object: MSExchangeTransport IsMemberOfResolver

• Use the Exchange Troubleshooting Assistant (ExTRA) to obtain Event Tracing for the Transport component. Click to select the IsMemberofResolver check box in the Trace Tags list.

  For more information, see the Scotch's Blog article Another Method of Obtaining ExTRA Traces. To obtain the Exchange Troubleshooting Assistant, see Microsoft Exchange Troubleshooting Assistant v1.1.

  The content of each blog and its URL are subject to change without notice. The content within each blog is provided "AS IS" with no warranties, and confers no rights. Use of included script samples or code is subject to the terms specified in the Microsoft Terms of Use.

• Modify distribution group cache settings. For example, modify the time for which group membership is stored in the cache, or increase the cache size. To do this, modify the EdgeTransport.exe.config file. The following excerpt from the EdgeTransport.exe.config file shows some of these settings.

  <configuration>
   <runtime>
      <gcServer enabled="true" />
   </runtime>
   <appSettings>
    <add key=" Transport_IsMemberOfResolver_ResolvedGroupsCache_ExpirationInterval"  value ="03:00:00"/>
    <add key="Transport_IsMemberOfResolver_ResolvedGroupsCache_CleanupInterval" value = "00:01:00"/>
    <add key="Transport_IsMemberOfResolver_ResolvedGroupsCache_PurgeInterval" value= "00:01:00"/>
    <add key="Transport_IsMemberOfResolver_ResolvedGroupsCache_MaxSize" value = "32MB"/>
    <add key="Transport_IsMemberOfResolver_ExpandedGroupsCache_ExpirationInterval" value = "03:00:00"/>
    <add key="Transport_IsMemberOfResolver_ExpandedGroupsCache_CleanupInterval" value = "01:00:00"/>
    <add key="Transport_IsMemberOfResolver_ExpandedGroupsCache_PurgeInterval" value= "00:05:00"/>
    <add key="Transport_IsMemberOfResolver_ExpandedGroupsCache_MaxSize" value = "512MB"/>
  </appSettings>
  

  The following tables contain more information about the cache settings that you can configure.

  Resolved Groups Settings

  Setting	Type	Default value	Description
  Transport_IsMemberOfResolver_ResolvedGroupsCache_ExpirationInterval	Date and Time	3 hours	Entries in the cache are marked as expired after ExpirationInterval passes. However, the entries are not immediately deleted from the cache. The minimum setting is 5 seconds. The maximum setting is 1 day.
  Transport_IsMemberOfResolver_ResolvedGroupsCache_CleanupInterval	Date and Time	1 hour	Entries are deleted from the cache after ExpirationInterval+CleanupInterval passes. However, if an entry is accessed between ExpirationInterval and ExpirationInterval+CleanupInterval, it is treated as a cache hit. Therefore, the current operation continues, and a background thread performs a new LDAP query to refresh the entry and re-add it to the cache. The minimum setting is 5 seconds. The maximum setting is 4 hours.
  Transport_IsMemberOfResolver_ResolvedGroupsCache_PurgeInterval	Date and Time	5 minutes	This entry affects how frequently the cache is purged of entries that are marked for deletion. However, it does not affect whether the cache returns an entry when queried. If an item is in the cache for more than ExpirationInterval+CleanupInterval, it is effectively deleted even if it is still physically in the cache and is not yet purged. The minimum setting is 5 seconds. The maximum setting is 4 hours.
  Transport_IsMemberOfResolver_ResolvedGroupsCache_MaxSize	Size	32 MB	The minimum size of the cache is 0 MB. The maximum size is 128 MB.

  Expanded Groups Settings

  Setting	Type	Default value	Description
  Transport_IsMemberOfResolver_ExpandedGroupsCache_ExpirationInterval	Date and Time	3 hrs	Entries in the cache are marked as expired after ExpirationInterval passes. However, the entries are not immediately deleted from the cache. The minimum setting is 5 seconds. The maximum setting is 1 day.
  Transport_IsMemberOfResolver_ExpandedGroupsCache_CleanupInterval	Date and Time	1 hour	Entries are deleted from the cache after ExpirationInterval+CleanupInterval passes. However, if an entry is accessed between ExpirationInterval and ExpirationInterval+CleanupInterval, it is treated as a cache hit. Therefore, the current operation continues. A background thread performs a new LDAP query to refresh the entry and re-add it to the cache. The minimum setting is 5 seconds. The maximum setting is 4 hours.
  Transport_IsMemberOfResolver_ExpandedGroupsCache_PurgeInterval	Date and Time	5 Minutes	This entry affects how frequently the cache is purged of all entries that are marked for deletion. However, it does not affect whether the cache returns an entry when queried. If an item is in the cache for more than ExpirationInterval+CleanupInterval, it is effectively deleted even if it is still physically in the cache and is not yet purged. The minimum setting is 5 seconds. The maximum setting is 4 hours.

• Resolve your issue by using self-support options, assisted support options, and other resources. You can access these resources from the Exchange Server Solutions Center. From this page, click Self-Support Options in the navigation pane to use self-help options. Self-help options include searching the Microsoft Knowledge Base, posting a question at the Exchange Server forums, and other methods. Alternatively, in the navigation pane, you can click Assisted Support Options to contact a Microsoft support professional. Because your organization may have a specific procedure for directly contacting Microsoft Product Support Services, be sure to review your organization's guidelines first.

For More Information

If you are not already doing so, consider running the Exchange tools, which have been created to help you analyze and troubleshoot your Exchange environment. These tools can help make sure that your configuration aligns with Microsoft best practices. They can also help you identify and resolve performance issues and improve mail flow. To run these tools, go to the Toolbox node of the Exchange Management Console. To learn more about these tools, see Managing Tools in the Toolbox.