fish6288
Enthusiast
Enthusiast

VM Defrag question

Im curious as to what people do for defrag on their virtual machines. Do you used the built in Windows defrag or a 3rd party defrag. How often do you do it and what are the pros and cons of defraging a VM disk.

I am under the impression that you should treat the VM as a normal server..which means you should run Defrag every so often..but i have seen other users disagree with this. With Server 2008 having a built in task for a weekly defrag i am wondering if users are using this feature on their Windows 2008 VMs.

Thanks

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Virtualinfra
Commander
Commander

As a best practise defrag are used on  virtual machine which are converted from physical machine.

If your disk is really big, then you can use defrag. For disk lesser than 100GB i really dont recommend this task on a virtual machine.

Thanks & Regards Dharshan S VCP 4.0,VTSP 5.0, VCP 5.0
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rickardnobel
Champion
Champion

fish6288 wrote:

How often do you do it and what are the pros and cons of defraging a VM disk.

If you are using Thin VMDK files then doing an internal defrag in the guest could make the VMDK file to grow very quickly.

Depending on your SAN this could also cause unintended actions, like increased replication of the LUN from lots of changed blocks.

If using a VMware aware backup tool (using the VADP api) which uses VM Changed Block Tracking it could also "cause" more data to be backed up due to a lot of movement of data inside the sectors of the virtual disk.

My VMware blog: www.rickardnobel.se
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