Data ONTAP Discussions

Compaction and Data Protection Volumes

We just upgraded to OnTAP 9.1P8. Production system is AFF so compaction is working by default. DR system is FAS8060. I enabled compaction at the aggregate level, but when I tried to enable at the volume level, it was only enabled on the root volumes. Is that because the other volumes are data protection volumes? Is there any value in turning on compaction on this system under these circumstances?

10 REPLIES

Re: Compaction and Data Protection Volumes

I typed this post too soon. Looks like it did enable for every volume on one node, but not the other. Looks like I had a typo on one entry and it caused the others to not run.

 

I do have a related question. I don't want to run the scan-old-data command on every volume, but am wondering if MOVING the volumes between aggregates would cause compaction to take effect. Any ideas?

Re: Compaction and Data Protection Volumes

If you have set on aggergates, volume move will do the job

Re: Compaction and Data Protection Volumes

Good to know, thank you!

Re: Compaction and Data Protection Volumes

I have two follow-ups:

 

1.  Is there any way can I check how much compaction saved on volumes? if so, what is the command?
      It seems to me I can only check on the aggregate.

2. while volume copy to a compaction enabled destiantion aggr,  the volume will be really compacted ?

Re: Compaction and Data Protection Volumes

@heightsnj, compaction is aggregate-level, that's why that's the only place you can check it. And yes, I did in fact move a bunch of volumes around and the compaction rate increased.

Re: Compaction and Data Protection Volumes

Thanks!

 

One more followup:

Let's say if I have a volume with no dedup and compression enabled on sas aggr. Then I do volume move to aff node, would this volume be deped and compressed while moved over to ssd? as by default, it will have dedup and compression enable, 

Re: Compaction and Data Protection Volumes

Not sure. You could enable it before moving and then move it to be sure. I would try one and see the results. 

Re: Compaction and Data Protection Volumes

I just did a test, the interesting is that if a volume without compression enabled on the source SAS aggr, then if I volume move to a SSD aggr which by default inline compression is enabled, when the move is completed, the compression is still not enabled. 

 

Why, should not it be enabled?

Re: Compaction and Data Protection Volumes

Is your SSD aggregate on an AFF system? If not, I'm not sure if turns on inline by default. Even if it's moved to AFF, I don't recall if it turns it on automatically with a vol move. The default definitely applies when creating new volumes on AFF.

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