- You are running Active Directory Domain Services (AD DS) or Lightweight Directory Service (LDS).
- You have a sizable database on which there is significant query load.
- You are seeing a large change rate against your database.
In this scenario, you receive warning events regularly that show that online defragmentation did not finish:
The event mentions that you can widen the window for the online defragmentation during off-peak hours. However, this is a generic event that is logged by the Active Directory Database Engine ESENT (Extensible Storage Engine). This engine is used by lots of Windows components and also server applications such as Microsoft Exchange Server. These applications may have different approaches to driving online defragmentation of the database.
For Active Directory, there are no settings to define the schedule to run online defragmentation.
Avoiding future events 602You should increase the version store size to avoid shortages. The registry setting to do this is as follows:
Note For more information, click the following article number to view the article in the Microsoft Knowledge Base:
Online defragmentation operational detailsOnline defragmentation runs as part of the garbage collection process. By default, it is triggered every twelve hours.
The job will run for one hour or half the garbage collection interval, whichever is the lower value. This means that you can shorten the online defragmentation interval only by using automated configuration.
However, Active Directory and LDS offer an operational attribute on the RootDSE object. You can use this attribute to start the online defragmentation. You can also specify a value in seconds of runtime. You set this value together with the command. You can use the repadmin tool to trigger the task. For example, you could run the following command:
Cleaning up the databaseSelect this option if you want a clean database and if database downtime is not a big worry.
You can remove the database fragmentation completely by performing an offline defragmentation. For more information, click the following article number to view the article in the Microsoft Knowledge Base:
Calculating the version store size974803 The domain controller runs slower or stops responding when the garbage collection process runs
Setting "doOnlineDefrag"Directory Database File Management Tasks
Decoupling garbage collection and online defragmentation
871003 An online defragmentation is automatically run after you run the Active Directory garbage collection process in Windows 2000 Server
Managing garbage collection execution
Directory Service Configuration Management Tasks
Article ID: 3079385 - Last Review: Jul 30, 2015 - Revision: 1