Although the Active Directory database is automatically defragmented while it is running (also known as online defragmentation), you can also stop Active Directory Domain Services (AD DS) to perform offline defragmentation to further reduce the size of the database. Offline defragmentation provides additional checks that can help ensure database integrity and performance.

Performing offline defragmentation

The following table lists the steps that you can take to perform offline defragmentation of the Active Directory database.

  Step Reference or procedure to use
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Review guidelines about performing offline defragmentation.

Returning Unused Disk Space from the Active Directory Database to the Windows File System (http://go.microsoft.com/fwlink/?LinkId=93219)

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Change the garbage collection logging level to determine how much free space is available.

Change the Garbage Collection Logging Level to 1 (http://go.microsoft.com/fwlink/?LinkId=93222)

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Back up system state.

Performing an Unscheduled Backup of a Domain Controller (http://go.microsoft.com/fwlink/?LinkId=93224)

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Stop AD DS.

Click Start, click Administrative Tools, and then click Services. Right-click Active Directory Domain Services, and then click Stop. When you are prompted to stop dependent services, click Yes.

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Perform the offline defragmentation procedure.

Compact the Directory Database File (Offline Defragmentation) (http://go.microsoft.com/fwlink/?LinkId=93225)

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Restart AD DS.

Click Start, click Administrative Tools, and then click Services. Right-click Active Directory Domain Services, and then click Start.