[gpfsug-discuss] How to shrink GPFS on DSSG's?

Laurence Horrocks-Barlow laurence at qsplace.co.uk
Wed Jul 20 07:40:55 BST 2022


Are you talking enclosures or subsystems here?
i.e. is it 5 separate dss subsystems each with 2 x x86 controllers or did you add 2 enclosures to the existing 3 dss subsystems?
If you added 2 new dss subsystems. Just suspend the disks on the 2 dss building blocks and remove the NSD’s created like any normal GPFS file system, the data will auto migrate to the remaining 3 building blocks. The 8+2 is local to the subsystem within the DA.
Once done remove those dss controllers from gpfs and do as you please, either keep the vdisks and DA’s or rebuild them.
If the latter, it becomes a bit more complex in fiddling with pdisks, and I don’t think it’s supported.
— Lauz
IBM Spectrum Scale wrote:
Adding Steve and Wes to provide guidance on ESS commands.
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 <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.
"Peter Childs" ---22-06-2022 03.36.33 PM---Having only just got an ESS I'm still learning how GNR works. as I read it there are currently two "
From: "Peter Childs" <p.childs at qmul.ac.uk>
To: "gpfsug-discuss at spectrumscale.org" <gpfsug-discuss at spectrumscale.org>
Date: 22-06-2022 03.36 PM
Subject: Re: [gpfsug-discuss] [EXTERNAL] How to shrink GPFS on DSSG's?
Sent by: "gpfsug-discuss" <gpfsug-discuss-bounces at gpfsug.org>
Having only just got an ESS I'm still learning how GNR works. as I read it there are currently two "breeds" of GNR, the version on the "DSS and ESS appliances" and the one in "Erasure Code Edition"
As I understand it from past talks using mmdeldisk to remove a disk works fine in none GNR editions but is not the best way to do the task.
My understanding is that you should
mmchdisk suspend/empty # so new data is not put on the disk but the disk remains available for read.
mmrestripefs -m # to move the data off the disk
mmdeldisk # to actually remove the disk which should be fast as its already been emptied.
We have done this with success in the past to migrate data between Raid6 arrays, with success.
I believe there are some commands with mmvdisk to re-shape recovery groups in GNR but I've not as yet worked out how they work.
Peter Childs
________________________________________
From: gpfsug-discuss <gpfsug-discuss-bounces at gpfsug.org> on behalf of Jaime Pinto <pinto at scinet.utoronto.ca>
Sent: Monday, June 20, 2022 7:04 PM
To: gpfsug-discuss at spectrumscale.org
Subject: [EXTERNAL] [gpfsug-discuss] How to shrink GPFS on DSSG's?
CAUTION: This email originated from outside of QMUL. Do not click links or open attachments unless you recognise the sender and know the content is safe.
I'm wondering if it's possible to shrink GPFS gracefully. I've seen some references to that effect on some presentations, however I can't find detailed instructions on any formal IBM documentation on how to do it.
About 3 years ago we launched a new GPFS deployment with 3 DSS-G enclosures (9.6PB usable).
Some 1.5 years later we added 2 more enclosures, for a total of 16PB, and only 7PB occupancy so far.
Basically I'd like to return to the original 3 enclosures, and still maintain the (8+2p) parity level.
Any suggestions?
Thanks
Jaime
---
Jaime Pinto - Storage Analyst
SciNet HPC Consortium - www.scinet.utoronto.ca
University of Toronto
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http://gpfsug.org/mailman/listinfo/gpfsug-discuss_gpfsug.org <http://gpfsug.org/mailman/listinfo/gpfsug-discuss_gpfsug.org> 
_______________________________________________
gpfsug-discuss mailing list
gpfsug-discuss at gpfsug.org
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Adding Steve and Wes to provide guidance on ESS commands.
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 <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.
"Peter Childs" ---22-06-2022 03.36.33 PM---Having only just got an ESS I'm still learning how GNR works. as I read it there are currently two "
From: "Peter Childs" <p.childs at qmul.ac.uk>
To: "gpfsug-discuss at spectrumscale.org" <gpfsug-discuss at spectrumscale.org>
Date: 22-06-2022 03.36 PM
Subject: Re: [gpfsug-discuss] [EXTERNAL] How to shrink GPFS on DSSG's?
Sent by: "gpfsug-discuss" <gpfsug-discuss-bounces at gpfsug.org>
Having only just got an ESS I'm still learning how GNR works. as I read it there are currently two "breeds" of GNR, the version on the "DSS and ESS appliances" and the one in "Erasure Code Edition"
As I understand it from past talks using mmdeldisk to remove a disk works fine in none GNR editions but is not the best way to do the task.
My understanding is that you should
mmchdisk suspend/empty # so new data is not put on the disk but the disk remains available for read.
mmrestripefs -m # to move the data off the disk
mmdeldisk # to actually remove the disk which should be fast as its already been emptied.
We have done this with success in the past to migrate data between Raid6 arrays, with success.
I believe there are some commands with mmvdisk to re-shape recovery groups in GNR but I've not as yet worked out how they work.
Peter Childs
________________________________________
From: gpfsug-discuss <gpfsug-discuss-bounces at gpfsug.org> on behalf of Jaime Pinto <pinto at scinet.utoronto.ca>
Sent: Monday, June 20, 2022 7:04 PM
To: gpfsug-discuss at spectrumscale.org
Subject: [EXTERNAL] [gpfsug-discuss] How to shrink GPFS on DSSG's?
CAUTION: This email originated from outside of QMUL. Do not click links or open attachments unless you recognise the sender and know the content is safe.
I'm wondering if it's possible to shrink GPFS gracefully. I've seen some references to that effect on some presentations, however I can't find detailed instructions on any formal IBM documentation on how to do it.
About 3 years ago we launched a new GPFS deployment with 3 DSS-G enclosures (9.6PB usable).
Some 1.5 years later we added 2 more enclosures, for a total of 16PB, and only 7PB occupancy so far.
Basically I'd like to return to the original 3 enclosures, and still maintain the (8+2p) parity level.
Any suggestions?
Thanks
Jaime
---
Jaime Pinto - Storage Analyst
SciNet HPC Consortium - www.scinet.utoronto.ca
University of Toronto
_______________________________________________
gpfsug-discuss mailing list
gpfsug-discuss at gpfsug.org
http://gpfsug.org/mailman/listinfo/gpfsug-discuss_gpfsug.org <http://gpfsug.org/mailman/listinfo/gpfsug-discuss_gpfsug.org> 
_______________________________________________
gpfsug-discuss mailing list
gpfsug-discuss at gpfsug.org
http://gpfsug.org/mailman/listinfo/gpfsug-discuss_gpfsug.org <http://gpfsug.org/mailman/listinfo/gpfsug-discuss_gpfsug.org> 
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