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Delete VV but Capacity not reduce

Posted: Sun Oct 20, 2013 8:59 pm
by ngthcongvn
I have a vv name ABC with 1.6TB and Capacity Free 1.3 TB

When i unexport vv ABC and remove vv ABC after ( on 3PAR Management Console )

But i check again Capacity still FREE 1.3 TB ( correctly is 2.9 TB )

I dont know why ? and please help me resolved problem . I use F-400 model

Thanks

Re: Delete VV but Capacity not reduce

Posted: Mon Oct 21, 2013 12:04 pm
by Christian
You may want to look at the CPG it should be 1.3TB free in that one.

Right click it and run Compact CPG

Re: Delete VV but Capacity not reduce

Posted: Mon Oct 21, 2013 2:06 pm
by Richard Siemers
A VV will have used and unused space, when it needs more space it gets it from the CPG.
A CPG will have used and unused space, when it needs more space it gets it from the PDs.

Same goes in reverse... when a vv is deleted, it returns the space to the CPG.
For a CPG to return space to the PDs you need to compact CPG.

Re: Delete VV but Capacity not reduce

Posted: Wed Oct 23, 2013 5:55 am
by ngthcongvn
Yes , i was run command "compactcpg -trimonly CPG_name"

But , it run for about 3 days , i see Capacity size not increase after i remove vv and run compactcpg

When i run command " showeventlog -d -debug -oneline -msg reclaim"

Display shows process reclaiming is working

Really, I don't know when reclaim finish !

Thanks

Re: Delete VV but Capacity not reduce

Posted: Fri Oct 25, 2013 1:22 pm
by Richard Siemers
Try "showtask" to see if you have any active tasks.

Also the trimonly setting does not do a full compaction.

Re: Delete VV but Capacity not reduce

Posted: Thu Nov 27, 2014 2:27 pm
by trarun0483
Hi you can use below dry run command and see what is actual space gain before running actual compactcpg

HP3Par1 cli% compactcpg -dr FC_SS6

Compacting CPG FC_SS6
Initial trim would reclaim 0 MB SA space, 0 MB SD space, and 0 MB USR space.
Would move 0 MB SA space, 0 MB SD space, and 0 MB USR space.
Final trim would reclaim 0 MB SA space, 0 MB SD space, and 0 MB USR space.

Re: Delete VV but Capacity not reduce

Posted: Fri Nov 28, 2014 8:54 am
by JohnMH
It depends on where you're looking for the space to be returned to.
When you delete volumes the chunklets first need to be cleaned before they are returned for use by the system, this is especially true for fpvv's as every chunklet is allocated upfront and so must be cleaned (zero's out) on deletion, you can see this by running the below.
CLI% showsys -space

If the uninitialized value is >0 it’s likely a large amount of data has been deleted and the blocks are in the process of being zero’d out before being returned to the system free pool. This process takes time and for non thin volumes every block allocated regardless of whether it was written needs to be zero’s out. There's no way to increase the speed of this process but it's only usually encountered during testing when large fully provisioned volumes are created, torn down and then recreated.

To view the cleaning process you can use :

CLI% showpdch –cng Specifies that information for chunklets that are being cleaned (reclaimed and zero’d after deletion) by the system are displayed, you can also use CLI% showpd –c

Once they're all clean a compactcpg which you should schedule will return these to the pool.