Log buffers may not be sufficient for servers with large numbers of mailboxes that are running Exchange Server 2003

[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: 2007-03-27

The Microsoft® Exchange Server Analyzer Tool queries the Active Directory® directory service to determine whether the following conditions are true:

  • The computer is running Exchange Server 2003.

  • The value of msExchESEParamLogBuffers is between 0 and 8,960.

  • The number of mailboxes in the storage group is more than 500.

The Exchange Server Analyzer queries the Win32_PerfRawData_MSExchangeIS_MSExchangeIS Microsoft Windows® Management Instrumentation (WMI) class to determine whether the following condition is true:

  • The value for VMLargestBlockSize is more than 150 million.

If all these conditions are true a warning is displayed.

Extensible Storage Engine (ESE) uses log buffers to hold transactions in memory before committing them to the transaction logs. If there are not sufficient log buffers, you may see excessive disk I/Os on the transaction log drive which will decrease performance.

To correct this warning

  1. In Active Directory Service Interfaces (ADSI) Edit, double-click the Configuration container, expand CN=Services, expand CN=Microsoft Exchange, and then expand CN=ExchangeOrganizationName.

  2. Expand CN=Administrative Groups, expand CN=AdministrativeGroupName, and then expand CN=Servers.

  3. Expand CN=ExchangeServerName, expand CN=InformationStore, right-click CN=Storage Group Name, and then click Properties.

  4. In the Select a property to view box, click msExchESEParamLogBuffers.

  5. In the Edit Attribute box, type 9000 for msExchESEParamLogBuffers, and then click Set.

  6. Click Apply, and then click OK.

  7. For the change to go into effect you must restart the Microsoft Exchange Information Store service.


If you incorrectly modify the attributes of Active Directory objects when you use ADSI Edit, the LDP (ldp.exe) tool, or another Lightweight Directory Access Protocol (LDAP) version 3 client, you may cause serious problems. These problems may require that you reinstall Microsoft Windows Server™ 2003, Exchange Server 2003, or both. Modify Active Directory object attributes at your own risk.

For more information, see Microsoft Knowledge Base article 328466, "ESE log buffers that are set too low can cause the Microsoft Exchange Information Store service to stop responding" (http://go.microsoft.com/fwlink/?linkid=3052&kbid=328466).