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farri304
Contributor
Contributor

Max VMDK size (Thin Provisioned) for Snapshots?

I have been getting Snapshot failures when trying to snap a guest with a 2Tb VMDK that is Thin Provisioned. Now I know that the maximum disk size VMFS supports is 2Tb -512bytes or ~2047. Typically when I am creating a Thick disk I always follow this guideline even accounting for the ~16Gb snapshot overhead, making my Thick provisioned VMDKs no larger than 2032Gb.

However I didn't think it mattered when using Thin Provisioning since the actual size of the VMDK is far less than what is provisioned. In my case a 2Tb (1.999Tb) Thin provisioned disk actually has a VMDK size of 150Gb leaving plenty of room for snapshot growth.

But after scanning the internet and finding this KB...

http://kb.vmware.com/selfservice/microsites/search.do?language=en_US&cmd=displayKC&externalId=101238...

it seems as though regardless of the Provisioning type (Thin/Thick) you must follow the standard of 2Tb -512bytes or 2047 and no more.

Has anyone else encountered this? I guess Id just feel better knowing others have seen this too and Im not crazy. Smiley Happy

Thanks all.

Joe

Twitter: @joefarri
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a_p_
Leadership
Leadership

It doesn't matter whether the virtual disk is thick or thin provisioned. What's important is the maximum size the snapshot can grow to, which is the provisioned disk size plus the overhead.

André

weinstein5
Immortal
Immortal

Welcome to the Community - yes that is correct the Maximum VMDK says hasnothing to do whther it is thin or thick provisioned but a limitation of thethe file format/SCSI access - 

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farri304
Contributor
Contributor

Thats what I thought. Thanks for your help guys.

Twitter: @joefarri
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