XADM: How to Configure the Exchange Server Online Defragmentation Time Window (244524)

IMPORTANT: This article contains information about modifying the registry. Before you modify the registry, make sure to back it up and make sure that you understand how to restore the registry if a problem occurs. For information about how to back up, restore, and edit the registry, click the following article number to view the article in the Microsoft Knowledge Base:

256986 Description of the Microsoft Windows Registry

SUMMARY

Exchange Server online defragmentation against the information store databases starts immediately after information store maintenance tasks have been completed. By default, the online defragmentation process runs for a minimum of fifteen minutes and it only runs for up to one hour after the information store maintenance scheduled window time. You can change these times by editing the registry.

NOTE: If information store maintenance does not complete any tasks against the information store databases and a previous online defragmenation finished in full, online defragmenation does not run.

MORE INFORMATION

WARNING: If you use Registry Editor incorrectly, you may cause serious problems that may require you to reinstall your operating system. Microsoft cannot guarantee that you can solve problems that result from using Registry Editor incorrectly. Use Registry Editor at your own risk.

To configure the length of time that online defragmentation runs after the information store maintenance window:

Start Registry Editor (Regedt32.exe).
Locate the following key in the registry:
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\MSExchangeIS\ParametersPrivate
On the Edit menu, click Add Value, and then add the following registry value:
Value Name: OLD Completion Time
Data Type: REG_DWORD
Value: Set the value to the number of seconds that you want to allow an overrun of the information store maintenance window (0 for no overrun, and the default is one hour: 1*60*60 seconds).
Add this value to the public information store as well in the following key:
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\MSExchangeIS\ParametersPublic
If you want to override the minimum length of time that online defragmentation runs, add the following value:
Value Name: OLD Minimum RunTime
Data Type: REG_DWORD
Value: Set the value to the minimum number of seconds that you want to let the old process run (the default is fifteen minutes: 15*60 seconds).
Quit Registry Editor.

NOTE: When the information store maintenance tasks and online defragmentation are complete, there is an opportunity for the cycle to begin again if there is time left in the information store maintenance window. A check is made every fifteen minutes to make sure that the server is in the information store maintenance time frame.