[gpfsug-discuss] GPFS Upgrade 3.5 -> 4.1

Peter Childs p.childs at qmul.ac.uk
Mon Oct 10 19:11:31 BST 2016


So in short we're saying, "mmchfs -V LATEST" increments a version number and allows new features to become possible, it does not start using them straight away. Hence

Directories will shrink in 4.1 but you need to run "mmchattr --compact" on all the old ones before anything actually changes. (new ones are fine) increasing the version number makes this possible but it does not actually do it, as doing it would mean walking every directory and updating stuff.





Peter Childs
Research Storage
ITS Research and Teaching Support
Queen Mary, University of London


---- Yuri L Volobuev wrote ----


Correct. mmchfs -V only done quick operations (that can be easily undone if something goes wrong). Essentially the big task here is to increase on-disk file system descriptor version number, to allow using those features that require a higher version. Bigger "conversion"-style tasks belong in mmmigratefs.

The only way to increase the inode size and the data block size is to format a new file system. This cannot be done on an existing file system.

yuri

[Inactive hide details for Jan-Frode Myklebust ---10/10/2016 07:35:48 AM---I've also always been worried about that one, but nev]Jan-Frode Myklebust ---10/10/2016 07:35:48 AM---I've also always been worried about that one, but never experienced it taking any time, I/O or inter

From: Jan-Frode Myklebust <janfrode at tanso.net>
To: gpfsug main discussion list <gpfsug-discuss at spectrumscale.org>,
Date: 10/10/2016 07:35 AM
Subject: Re: [gpfsug-discuss] GPFS Upgrade 3.5 -> 4.1
Sent by: gpfsug-discuss-bounces at spectrumscale.org

________________________________



I've also always been worried about that one, but never experienced it taking any time, I/O or interruption. I've the interpreted it to just start using new features, but not really changing anything with the existing metadata. Things needing on disk changes are probably put in mmmigratefs I have not heard about anything needing mmmigratefs since GPFS v3.3 (fs version 11.03) added fast extended attributes.

Would be great to hear otherwize, or confirmations.


-jf
man. 10. okt. 2016 kl. 14.32 skrev Peter Childs <p.childs at qmul.ac.uk<mailto:p.childs at qmul.ac.uk>>:

We are finishing upgrading our GPFS cluster of around 250 (client) nodes from GPFS 3.5.0.31 to Spectrum Scale 4.1.1.8, and have just about upgraded all the computers.

We are looking at running the "mmchfs -V LATEST" step and where wondering how much io this takes and if it was likely to interrupt service?

We are looking at upgrading to 4.2 but plan to do that via Multi-cluster and AFM as we are integrating new hardware and wish to increase the block and inode size at the same time.

Peter Childs
Research Storage Expert
ITS Research Infrastructure
Queen Mary, University of London

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