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3 Silver

Need informations about Subscription % and FASTVP on Thin pools

Hi,

I am looking for an information regarding the subscription % of a pool in a VMAX40K. 

--> I have 1x Lun of 1000Go, i bind it in the middle tier and activate FAST, by policy 200Go goes into EFD.

Question #1: Will the subscription % of the middle tier pool change after the data has been move to EFD or other pools ?

Question #2: What happen if you disable FASTVP completly ?  Will all the storage capacity that FASTVP sent to other pools by policy will return                     automatically to the BIND pool (middle tier) ?

Thank you,

Christian Carrier

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Rohang,

slight correction on your reply..

The subscription value of a pool is the ratio of the capacity of the thin devices bound to the pool to the capacity of the pool itself.  A pool can be oversubscribed but not fully allocated meaning there is still free space in  the pool.

The allocation % will change as tracks move out of the tier due to fast VP movement but the actual subscription will not change.

Please refer to https://support.emc.com/docu31003_fast-vp-for-symmetrix-vmax-theory-and-best-practices-for-planning-and-performance.pdf

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3 Silver

Hello Christian,

Yes, the subscription % of the middle tier should change after data has moved over to the EFD tier or to the other pools contained in the policy.

When you disable FAST VP completely, or when you disassociate an SG from a FAST VP policy, you will need to explicitly do a VLUN migration (#symmigrate) to move the extents back to where the TDEV was originally bound to. Else they stay where they are.


regards.

Rohang,

slight correction on your reply..

The subscription value of a pool is the ratio of the capacity of the thin devices bound to the pool to the capacity of the pool itself.  A pool can be oversubscribed but not fully allocated meaning there is still free space in  the pool.

The allocation % will change as tracks move out of the tier due to fast VP movement but the actual subscription will not change.

Please refer to https://support.emc.com/docu31003_fast-vp-for-symmetrix-vmax-theory-and-best-practices-for-planning-and-performance.pdf

Community Accepted Solution

My bad.

Yes the allocation% will change, not the subscription %

regards

Thank you both for your answers.

P.S: Sorry for the late delay of my answer.

Regards

No problem glad to help out. Hopefully the answer was what you were looking for.

Sent from my Samsung device

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