[gpfsug-discuss] Same file opened by many nodes / processes

[IBM Spectrum Scale]

What is in the dump that indicates the metanode is moving around?  Could 
you please provide an example of what you are seeing?

You noted that the access is all read only, is the file opened for read 
only or for read and write?

What makes you state that this particular file is interfering with the 
scan done by mmbackup?  Reading a file, no matter how large should 
significantly impact a policy scan.

What version of Spectrum Scale are you running and how large is your 
cluster?

Regards, The Spectrum Scale (GPFS) team

------------------------------------------------------------------------------------------------------------------
If you feel that your question can benefit other users of  Spectrum Scale 
(GPFS), then please post it to the public IBM developerWroks Forum at 
https://www.ibm.com/developerworks/community/forums/html/forum?id=11111111-0000-0000-0000-000000000479
. 

If your query concerns a potential software error in Spectrum Scale (GPFS) 
and you have an IBM software maintenance contract please contact 
1-800-237-5511 in the United States or your local IBM Service Center in 
other countries. 

The forum is informally monitored as time permits and should not be used 
for priority messages to the Spectrum Scale (GPFS) team.



From:   Peter Childs <p.childs at qmul.ac.uk>
To:     "gpfsug-discuss at spectrumscale.org" 
<gpfsug-discuss at spectrumscale.org>
Date:   07/10/2018 10:51 AM
Subject:        [gpfsug-discuss] Same file opened by many nodes / 
processes
Sent by:        gpfsug-discuss-bounces at spectrumscale.org



We have an situation where the same file is being read by around 5000
"jobs" this is an array job in uge with a tc set, so the file in
question is being opened by about 100 processes/jobs at the same time.

Its a ~200GB file so copying the file locally first is not an easy
answer, and these jobs are causing issues with mmbackup scanning the
file system, in that the scan is taking 3 hours instead of the normal
40-60 minutes.

This is read only access to the file, I don't know the specifics about
the job.

It looks like the metanode is moving around a fair amount (given what I
can see from mmfsadm saferdump file)

I'm wondering if we there is anything we can do to improve things or
that can be tuned within GPFS, I'm don't think we have an issue with
token management, but would increasing maxFileToCache on our token
manager node help say?

Is there anything else I should look at, to try and attempt to allow
GPFS to share this file better.

Thanks in advance

Peter Childs

-- 
Peter Childs
ITS Research Storage
Queen Mary, University of London
_______________________________________________
gpfsug-discuss mailing list
gpfsug-discuss at spectrumscale.org
http://gpfsug.org/mailman/listinfo/gpfsug-discuss






-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://gpfsug.org/pipermail/gpfsug-discuss_gpfsug.org/attachments/20180710/ae72ce2f/attachment.htm>