[gpfsug-discuss] question on viewing block distribution across NSDs

[Greg.Lehmann at csiro.au]

I was going to keep mmdf in mind, not gpfs.snap. I will now also keep in mind that mmdf can have an impact as at present we have spinning disk for metadata. The system I am playing around on is not production yet, so I am safe for the moment.

Thanks again.

From: gpfsug-discuss-bounces at spectrumscale.org [mailto:gpfsug-discuss-bounces at spectrumscale.org] On Behalf Of Knister, Aaron S. (GSFC-606.2)[COMPUTER SCIENCE CORP]
Sent: Thursday, 30 March 2017 9:55 AM
To: gpfsug main discussion list <gpfsug-discuss at spectrumscale.org>
Subject: Re: [gpfsug-discuss] question on viewing block distribution across NSDs

I don't necessarily think you need to run a snap prior, just the output of mmdf should be enough. Something to keep in mind that I should have said before-- an mmdf can be stressful on your system particularly if you have spinning disk for your metadata. We're fortunate enough to have all flash for our metadata and I tend to take it for granted some times :)

From: greg.lehmann at csiro.au<mailto:greg.lehmann at csiro.au>
Sent: 3/29/17, 19:52
To: gpfsug main discussion list
Subject: Re: [gpfsug-discuss] question on viewing block distribution across NSDs
Thanks. I don’t have a snap. I’ll keep that in mind for next time I do this.

From: mailto:gpfsug-discuss-bounces at spectrumscale.org] On Behalf Of Knister, Aaron S. (GSFC-606.2)[COMPUTER SCIENCE CORP]
Sent: Thursday, 30 March 2017 9:45 AM
To: gpfsug main discussion list <gpfsug-discuss at spectrumscale.org<mailto:gpfsug-discuss at spectrumscale.org>>
Subject: Re: [gpfsug-discuss] question on viewing block distribution across NSDs

Hi Greg,

You could run an mmdf which will show you how full each NSD is. I'm not sure how to look back in time though to see the fs before the restripe. Do you perhaps have a gpfs.snap you took somewhat recently before the restripe? Maybe an internaldump in /tmp/mmfs somewhere?

From: greg.lehmann at csiro.au<mailto:greg.lehmann at csiro.au>
Sent: 3/29/17, 19:21
To: gpfsug main discussion list
Subject: [gpfsug-discuss] question on viewing block distribution across NSDs
Hi All,
               I added some NSDs to an existing filesystem and ran mmrestripefs. I was sort of curious to see what the distribution looked like before and after the restripe. Is there any way of looking at it?

Cheers,

Greg.
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