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Why "compactcpg" is not ran automatically by default?
https://3parug.com/viewtopic.php?f=18&t=3245
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Author:  godosh [ Wed Jul 17, 2019 7:58 am ]
Post subject:  Why "compactcpg" is not ran automatically by default?

We don't have a dedicated "storage team" here to manage our 3PAR, we manage every components in the datacenter as part of our daily tasks, so we don't have much time to deal with obscure manual maintenance tasks required by the 3PAR.

So why does the "compactcpg" and "freespace" commands are not ran automatically by default? And is there any reasons why I may not schedule a script to run those 2 commands on a monthly basis?

Do you usually put those maintenance tasks in the "Change Approval Board" (CAB) in your office?

Author:  ailean [ Wed Jul 17, 2019 10:45 am ]
Post subject:  Re: Why "compactcpg" is not ran automatically by default?

It would depend on your usage, if you only had one CPG then created and later deleted volumes you wouldn't be losing any space. The space claimed by the CPG will be used next time you create a volume or a remaining volume grows so it's still available.

In this case running compactcpg would just add extra load to tidy up and take space away from the CPG only for it to claim it back at a later date again.

If you had a lot of CPGs and all the growth stopped in some and you deleted some of the volumes but other CPGs still had growth in them then yes compactcpg would be handy to free space from the stagnant CPGs so the active CPGs could claim it.

We rarely get a lot of volume deletions so on the odd occasion it does happen I tend to manually kick off a compactcpg afterwards if it's multiple TBs (I might just do a trim only if it's in the middle of day).

I don't put compactcpg to change control, but do take into account the load on the array before using. If you scripted it you might want to get approval for the time window to make sure it doesn't clash with backup windows or other known heavy load times.

Author:  MammaGutt [ Wed Jul 17, 2019 1:16 pm ]
Post subject:  Re: Why "compactcpg" is not ran automatically by default?

Agreed. If you want both to run automatically, when do you want to run them? Compactcpg does a lot of internal movement in LDs in direct conflict with a lot of other tasks. Compactcpg is really only needed when you have multiple CPGs allocating from the same set of disks and you've recently deleted a lot of stuff. Why not put it in your process document at the end of every VV delete?

As for freespace, that only does any real work when you've had snapshots and then deleted them all. That doesn't happen all that often in my experience... Primarily I've done this as cleanup after testing or stopping sync replication for a period of time.

Author:  MBILC [ Thu Jul 18, 2019 12:20 pm ]
Post subject:  Re: Why "compactcpg" is not ran automatically by default?

Also if your not wanting to manage the back end, use VVOl's

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