Impact of running a compactcpg -dr on general performances

[nicoroy123]

Hi friends,
Following the recommandation of HP personnel, I am about to run a compactcpg -dr on a particular CPG on which I hope to reclame free space.
I am wondering if any of you could comment on the performance impact of running such command in a prod environnment?

Of course I want to run it off hours but still, how bad is it?

-F-200, 16 x 600GB 15K RPM, RAID5 3+1

Regards

[Richard Siemers]

With 16x 600 gb drives... you have about 2880 iops to "play with" (180 per drive). Do you have "System Reporter" collecting your stats? If so, pull a Physical Disk performance report for a week span, and see how many iops you average for the entire system, and when your peaks/valleys are, and how close you get to your glass ceiling of 2880 iops. Reviewing the same report after the compact is done will help illustrate the impact it had on your environment, good information to keep around for next time, perhaps you will be able to run it during the day without hesitation.

On average, our highest work loads are at night during backups and batch processing, so we have the highest surplus of unused iops during the day. We run all our compacts as well as "D.O." moves during the day without issue, or noticeable impact.

As for compacting the CPG, I use the GUI, right click the CPG and click compact. It shows a pre-plan of what it will do before you execute it, and gives you the check box option to just free up any already empty LDs and not move any data around to free up additional LDs, I generally let it do a full run and compact the whole cpg.