Default ESE log buffers have been changed
Topic Last Modified: 2005-11-18
The Microsoft® Exchange Server Analyzer Tool searches the Active Directory® directory service for the value for the msExchESEParamLogBuffers attribute of each storage group on the Exchange Server computer. If the Exchange Server Analyzer finds the value for msExchESEParamLogBuffers equal to 512, a non-default configuration message is displayed.
The msExchESEParamLogBuffers storage group attribute governs the number of Extensible Storage Engine (ESE) log buffers that are used by the Exchange information store. ESE uses a set of log buffers to hold information in RAM before it writes to the transaction logs. Using these buffers improves transaction logging performance. For large servers, the default value of 84 is too low. This can cause excessive disk I/O operations to the transaction log drive and, therefore, significant performance degradation if the server is under load or if users are sending large messages. Increasing the number of ESE log buffers improves performance, although it also causes more virtual memory usage.
To correctly set this value, use the following information:
For Exchange 2000 Server, Exchange 2000 Server Service Pack 1 (SP1), or Exchange 2000 Server Service Pack 2 (SP2), set this value to 9000.
For Exchange 2000 Server Service Pack 3 (SP3), set this value to 512.
For Exchange Server 2003, a default value of 500 is used, and you should change the value for the msExchESEParamLogBuffers attribute to 9000.
|If you previously tuned log buffers to 9000, make sure that you manually reduce this setting after you apply Exchange 2000 Server SP3. This change is not made automatically when you install Exchange 2000 Server SP3.|
If you have log stalls, this may be caused by too low a buffer, and you can raise this value up to 9000. The Database\Log Record Stalls/sec performance counter can be monitored to determine whether log stalls are occurring. Do not use a value greater than 9000, as that can corrupt transaction log files.
|Log Record Stalls/sec is the number of log records that cannot be added to the log buffers per second because they are full. If this counter is non-zero most of the time, the log buffer size may be a bottleneck.|
You must correct the value using a tool such as the Active Directory Service Interfaces (ADSI) Edit snap-in, the LDP (ldp.exe) tool, or any other Lightweight Directory Access Protocol (LDAP) version 3 client.
|If you incorrectly modify the attributes of Active Directory objects when you use ADSI Edit, the LDP tool, or another 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.|
Start ADSI Edit.
Double-click the Configuration container, expand CN=Services, expand CN=Microsoft Exchange, and then expand CN=<ExchangeOrganizationName>.
Expand CN=Administrative Groups, expand CN=<AdministrativeGroupName>, and then expand CN=Servers.
Expand CN=<ServerName>, expand CN=InformationStore, right-click CN=<StorageGroupName>, and then click Properties.
In the Attribute Editor, click the msExchESEParamLogBuffers attribute, and then click Edit.
In the Edit Attribute box, set the value to 512 for Exchange 2000 Server or 9000 for Exchange Server 2003.
Click Apply, and then click OK.
Close ADSI Edit, and then restart the Microsoft Exchange Information Store service for the change to take effect.
For more information about ESE log buffers, see the Microsoft Knowledge Base article 328466, "XADM: ESE Log Buffers That Are Set Too Low Can Cause the Store to Stop Responding" (http://go.microsoft.com/fwlink/?linkid=3052&kbid=328466).
For more information about using the LDP tool, see the Knowledge Base article 260745, "XADM: Using the LDP Utility to Modify Active Directory Object Attributes" (http://go.microsoft.com/fwlink/?LinkId=3052&kbid=260745).
For more information about working with ADSI Edit, see the topic "Adsiedit.msc: ADSI Edit" in the Windows Server Help.