[gpfsug-discuss] How to shrink GPFS on DSSG's?
Jonathan Buzzard
jonathan.buzzard at strath.ac.uk
Mon Jun 20 19:40:16 BST 2022
On 20/06/2022 19:04, Jaime Pinto wrote:
>
> I'm wondering if it's possible to shrink GPFS gracefully.
Yes absolutely, been possible since at least version 2.2 and probably older.
> 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.
>
Use mmdeldisk to remove the NSD(s) from a file system. This will take a
while so I recommend in the *STRONGEST* possible terms running it in a
screen or tmux session. By a while it could be days or even weeks
depending on how much data needs to be moved about.
Once you have removed the NSD's from a file system then you can use
mmdelnsd to wipe the NSD descriptors from the disks if necessary.
> 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?
Not being sarky but really use Google. Say "gpfs remove nsd from file
system" and select the first link!
JAB.
--
Jonathan A. Buzzard Tel: +44141-5483420
HPC System Administrator, ARCHIE-WeSt.
University of Strathclyde, John Anderson Building, Glasgow. G4 0NG
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