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Re: HP StoreVirtual VSA -- is 'thin on thin' okay to do??

 
Tom Lyczko
Super Advisor

HP StoreVirtual VSA -- is 'thin on thin' okay to do??

Just recently had set up and configured StoreVirtual VSA on 2 ESXi hosts with a FOM.

 

The VMs are all thin provisioned and so are the VSA volumes thin provisioned.

 

Is this okay to do, are there any unseen risks or gotchas involved??

 

Not many VMs are installed to the volumes, not much storage is being used, so I could change the VSA back to full provisioned if need be...

 

Thank you, Tom

3 REPLIES 3
oikjn
Honored Contributor

Re: HP StoreVirtual VSA -- is 'thin on thin' okay to do??

Technically you can do that, but thin does have a slight performance impact which may or may not matter to you.  The bigger concern would be you are using Thin on top of thin which could be easy to lose track of and suddenly your critical SAN stops functioning.  Better to follow their suggestions and provide the VSAs with thick drives so you don't have to worry about those running out of space...  You shouldn't have any other drives on those volumes anyway because of resource contention so what is the point of making them thin ;)  

Tom Lyczko
Super Advisor

Re: HP StoreVirtual VSA -- is 'thin on thin' okay to do??

It seems you're saying leave the vSphere thin provisioning as it and put the VSA volumes back to thick, correct??

I'm definitely not changing the vSphere thin provisioning. :) :)

I hope more people reply, I also asked HP support, to get a different perspective.


Thank you, Tom

oikjn
Honored Contributor

Re: HP StoreVirtual VSA -- is 'thin on thin' okay to do??

If you are talking about vsphere thin provisioning for the volume which stores the VSA, then I'm suggesting the opposite.  You can keep the VMs thin provisioned on the volumes presented by the VSA to vsphsere, but I would not present thin volumes TO the VSA.

 

The last thing you want is the VSA crashing because the storage space it is assuming it has actually isn't there.  Also, I'm pretty sure that it will expand rapidly because of how the SAN stores its data and snapshots.  Maybe esx can keep up with shrinking it down, but it might not zero our erase its space once it uses it for something so it won't actually go thin.  Keep in mind that if you present a thin store to the VSA, you will be running Thin (hardware to VSA) on top of Thin (VSA to LUN) on top of Thin (vsphere to VM).  Doing the last two is reasonable, but adding that first one really makes things risky.