Microsoft KB Archive/283691

= XADM: Store Backup Runs More Slowly as Database Becomes Fragmented =

Article ID: 283691

Article Last Modified on 2/20/2007

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APPLIES TO


 * Microsoft Exchange 2000 Server Standard Edition

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This article was previously published under Q283691



SYMPTOMS
Over a period of time, as more data is added to an information store database, the performance of the regular online backup decreases. By running a disk analysis tool, you can see that the Priv.edb or Pub.edb file consists of many thousands of fragments.



CAUSE
Whenever an Extensible Storage Engine (ESE) file is extended, it is only extended in 1 megabyte (MB) amounts because ESE is calling a function to ensure that the file size is being updated each time the file is extended. This ensures that administrators can see how big the files currently are.

In addition, an Active Directory attribute which specifies the size of new file extensions is not being observed.



RESOLUTION
To resolve this problem, obtain the latest service pack for Microsoft Exchange 2000 Server. For additional information, click the following article number to view the article in the Microsoft Knowledge Base:

301378 XGEN: How to Obtain the Latest Exchange 2000 Server Service Pack

The English version of this fix should have the following file attributes or later:

Component: ESE

Component: Information Store



WORKAROUND
Perform an offline defragmentation of the database.



STATUS
Microsoft has confirmed that this is a problem in Microsoft Exchange 2000 Server.

This problem was first corrected in Microsoft Exchange 2000 Server Service Pack 1.



MORE INFORMATION
The fix now calls another Microsoft Windows function that retains the feature of the file size being updated, but ensures that new fragments are allocated in 16 MB sizes, if 16 MB has been set in Active Directory as the extension size.

WARNING: If you use the ADSI Edit snap-in, the LDP utility, or any other LDAP version 3 client, and you incorrectly modify the attributes of Active Directory objects, you can cause serious problems. These problems may require you to reinstall Microsoft Windows 2000 Server, Microsoft Exchange 2000 Server, or both. Microsoft cannot guarantee that problems that occur if you incorrectly modify Active Directory object attributes can be solved. Modify these attributes at your own risk.

To set the extension size to 16 MB, use ADSI Edit (provided with Microsoft Windows 2000 Support Tools):
 * 1) Locate the storage group which is to be changed, and open its properties.
 * 2) Select the msExchESEParamDbExtensionSize optional attribute. This has a default value of 256. Change this to 4096.
 * 3) After you set the new value, restart the information store. Note that this extension size applies to both the .edb and the .stm files.

Additional query words: defrag performance backup speed

Keywords: kbbug kbfix kbqfe KB283691

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