[gpfsug-discuss] Running gpfs.snap outside of problems

[Sobey, Richard A]

Thanks Kevin and J-F, I appreciate your thoughts.

I’ll go with “no” then as my answer ☺

Cheers
Richard

From: gpfsug-discuss-bounces at spectrumscale.org [mailto:gpfsug-discuss-bounces at spectrumscale.org] On Behalf Of Kevin D Johnson
Sent: 09 March 2017 19:48
To: gpfsug-discuss at spectrumscale.org
Cc: gpfsug-discuss at spectrumscale.org
Subject: Re: [gpfsug-discuss] Running gpfs.snap outside of problems

I've never heard of running a gpfs.snap every few hours, but it is technically possible.  Probably not advisable except in the most limited of circumstances.  I wouldn't do it unless Support or another technical resource you trust says to do so.

You can limit the snap to run on a few nodes versus a whole cluster and that way limit the effect it has overall.  You can also specify a directory outside GPFS to write the snap file.

Kevin D. Johnson, MBA, MAFM
Spectrum Computing, Senior Managing Consultant

IBM Certified Deployment Professional - Spectrum Scale V4.1.1
IBM Certified Deployment Professional - Cloud Object Storage V3.8
IBM Certified Solution Advisor - Spectrum Computing V1

720.349.6199 - kevindjo at us.ibm.com



----- Original message -----
From: Jan-Frode Myklebust <janfrode at tanso.net>
Sent by: gpfsug-discuss-bounces at spectrumscale.org
To: "gpfsug-discuss at spectrumscale.org" <gpfsug-discuss at spectrumscale.org>
Cc:
Subject: Re: [gpfsug-discuss] Running gpfs.snap outside of problems
Date: Thu, Mar 9, 2017 11:30 AM


There's a manual for it now.. and it points out "The tool impacts performance.." Also it has caused mmfsd crashes for me earlier, so I've learned to be weary of running it..

The manual also says it's collecting using mmfsadm, and the mmfsadm manual warns that it might cause GPFS to fail ("in certain rare cases").

I wouldn't dare running it every few hours.



-jf
tor. 9. mar. 2017 kl. 17.12 skrev Sobey, Richard A <r.sobey at imperial.ac.uk<mailto:r.sobey at imperial.ac.uk>>:

Hi all,



Is there any best practice as to when to run a gpfs.snap, and the impact it will have on a healthy cluster? Some of my colleagues are keen to gather a snap for example every 2 hours to assist in problem determination.



I can elaborate on the “why” part of this if needed but I’m not fully convinced it would help. Said I’d look into it though so I’m asking the question.



Cheers

Richard
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