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

[Luis Bolinches]

Hi

I’d like to add that you will be removing, assuming identical systems and networks, 2/5 of your throughput. Hope that is ok too. 

--
Cheers

> On 20. Jun 2022, at 21.42, Jonathan Buzzard <jonathan.buzzard at strath.ac.uk> wrote:
> 
> 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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