[gpfsug-discuss] Is GPFS starting NSDs automatically?

[Bryan Banister]

For non-stretch clusters, I think best practice would be to have an administrator analyze the situation and understand why the NSD was considered unavailable before attempting to start the disks back in the file system.  Down NSDs are usually indicative of a serious issue.

However I have seen a transient network communication problems or NSD server recovery cause a NSD Client to report a NSD as failed.  I would prefer that the FS manager check first that the NSDs are actually not accessible and that there isn’t a recovery operation within the NSD Servers supporting an NSD before marking NSDs as down.  Recovery should be allowed to complete and a NSD client should just wait for that to happen.  NSDs being marked down can cause serious file system outages!!

We’ve also requested that a settable retry configuration setting be provided to have NSD Clients retry access to the NSD before reporting the NSD as failed (https://www.ibm.com/developerworks/rfe/execute?use_case=viewRfe&CR_ID=104474 if you want to add a vote!).

Cheers,
-Bryan

From: gpfsug-discuss-bounces at spectrumscale.org [mailto:gpfsug-discuss-bounces at spectrumscale.org] On Behalf Of Jan-Frode Myklebust
Sent: Wednesday, August 09, 2017 7:23 AM
To: gpfsug main discussion list <gpfsug-discuss at spectrumscale.org>
Subject: Re: [gpfsug-discuss] Is GPFS starting NSDs automatically?

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If you do a "mmchconfig restripeOnDiskFailure=yes", such a callback will be added for node-join events. That can be quite useful for stretched clusters, where you want to replicate all blocks to both locations, and this way recover automatically.

  -jf

On Wed, Aug 9, 2017 at 2:14 PM, Oesterlin, Robert <Robert.Oesterlin at nuance.com<mailto:Robert.Oesterlin at nuance.com>> wrote:
By default, GPFS does not automatically start down disks. You could add a callback “downdisk” via mmaddcallback that could trigger a “mmchdisk start” if you wanted. If a disk is marked down, it’s better to determine why before trying to start it as it may involve other issues that need investigation.

Bob Oesterlin
Sr Principal Storage Engineer, Nuance



From: <gpfsug-discuss-bounces at spectrumscale.org<mailto:gpfsug-discuss-bounces at spectrumscale.org>> on behalf of "Tomasz.Wolski at ts.fujitsu.com<mailto:Tomasz.Wolski at ts.fujitsu.com>" <Tomasz.Wolski at ts.fujitsu.com<mailto:Tomasz.Wolski at ts.fujitsu.com>>
Reply-To: gpfsug main discussion list <gpfsug-discuss at spectrumscale.org<mailto:gpfsug-discuss at spectrumscale.org>>
Date: Wednesday, August 9, 2017 at 6:33 AM
To: "gpfsug-discuss at spectrumscale.org<mailto:gpfsug-discuss at spectrumscale.org>" <gpfsug-discuss at spectrumscale.org<mailto:gpfsug-discuss at spectrumscale.org>>
Subject: [EXTERNAL] [gpfsug-discuss] Is GPFS starting NSDs automatically?


Does GPFS start “down” disks in a filesystem automatically? For instance, when connection to NSD is recovered, but it the meantime disk was put in “down” state by GPFS. Will GPFS in such case start the disk?


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