Create a defragmentation scheduled task in Windows Server 2008

Managing disk defragmentation is one of the finesse areas of IT administration. Here's a tip on how to manage defragmentation with Group Policy for Windows Server 2008.

In my previous Windows Server tip, I outlined how to set a server's individual defragmentation schedule. It's a good solution for one server, but what if you have a large collection of servers? This is where Group Policy comes to the rescue.

Windows Server 2008 introduces a new extension of Group Policy that allows scheduled tasks to be deployed via a Group Policy Object (GPO). In the case of disk defragmentation, you can configure a GPO to run a defragmentation task. We have to borrow the scripting options from the built-in task, specifically the %windir%\system32\defrag.exe command coupled with the -c parameter.

You configure scheduled tasks through GPOs in the Computer Configuration | Preferences | Control Panel Settings | Scheduled Tasks section of the Group Policy editor (Figure A). Figure A

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Once the scheduled task is made via the GPO, it is located in a different area of the Task Scheduler (taskschd.msc) snap-in compared to the built-in task from the default installation. The GPO tasks will appear above the Microsoft folder in the root of the Task Scheduler Library folder (Figure B). Figure B

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Pushing a defrag task out with a GPO, on the one hand, is good because it ensures a consistent configuration deployed quickly; on the other hand, it may be risky to launch a series of tasks that would send a burst of I/O on the storage system. If this mechanism is selected, here are guidelines for deploying GPOs for defrag:
  • Go very granular in the organizational unit structure with different schedules to distribute the workload.
  • Consider running this on client PCs.
  • Be aware of multiple iterations of defragmentation where SANs are in use.
  • Consider consolidated effects of virtual machines.

Do you feel that defragmentation tasks should be centrally managed via Group Policy or local on each server? Share your comments in the discussion.

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