Topic Last Modified: 2010-09-02

The Microsoft Exchange Server 2010 Management Pack for System Center Operations Manager includes a performance data collection engine that is used to query performance counter objects on computers running Exchange 2010. For this Operations Manager rule, data is collected by using the performance counter specified in the Details table.

To review the value of the performance counter that generated this alert, in Operations Manager, double-click this alert, and then click the General tab. Review the description of the alert that includes the variables specific to your environment.

Details

Product Name

Exchange

Product Version

14.0 (Exchange 2010)

Object Name

MSExchangeTransport IsMemberOfResolver

Counter Name

IsMemberOfResolver ResolvedGroups Cache Size Percentage

Instance Name

Transport

Sample Interval

60

Server Role

Ex14. Common

Warning Threshold

66

Rule Path

Microsoft Exchange Server/Exchange 2010/Common Components/Hub Transport and Edge Transport/Transport

Rule Name

Transport IsMemberOfResolver ResolvedGroups Cache nearing capacity - Yellow(>66).

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.

Note:
This cache is not used for recipient name resolution during message delivery. It is used only for rule processing.

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.

    Copy Code
    <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 others. 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 Technical Support, be sure to review your organization's guidelines first.

For More Information

If you are not already doing so, consider running the Exchange tools 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, improve mail flow, and better manage disaster recovery scenarios. 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.