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 
if you want to add a vote!).


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

Note: External Email
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 


On Wed, Aug 9, 2017 at 2:14 PM, Oesterlin, Robert 
<<>> 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

 on behalf of 
Reply-To: gpfsug main discussion list 
Date: Wednesday, August 9, 2017 at 6:33 AM
To: "<>" 
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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