[lustre-discuss] Is live upgrade of 2.4 to 2.5 unproblematic?

[Dilger, Andreas]

We typically test 2.x->2.x+1 upgrades, both live and offline, for every version of Lustre. That said, there are a large number of possible states that may occur with a running job, so it isn't possible to test everything. If you are ready to abort the long-running job, then trying the live upgrade and having to restart if it fails isn't any worse. 

I'd always recommend to make a backup of the MDT, regardless of whether you are doing an upgrade or not, since it is a lot easier to restore only the MDT if there are problems than to restore the whole filesystem. 

Cheers, Andreas

> On Jul 8, 2016, at 09:08, Peter Bortas <bortas at gmail.com> wrote:
> 
> I'm upgrading a few ZFS backed filesystems from 2.4.2 to 2.5.3 (both
> from the llnl chaos branch). Clients are already running 2.5EE. It's a
> simple setup with no failover or mirroring of MDSs or OSSs. Originally
> the plan was to do this with the filesystems unmounted on the clients,
> but it looks like it will be hard to get a window to do that any time
> soon.
> 
> Are there any known problems just doing an online upgrade 2.4 -> 2.5?
> 
> Is the recommended method still OSSs first and MDS last?
> 
> (Obviously the clients will lock up if they access these filesystems,
> but locking them up for a fraction of a day beats aborting a 7 day
> compute job.)
> 
> Regards,
> -- 
> Peter Bortas, NSC
> _______________________________________________
> lustre-discuss mailing list
> lustre-discuss at lists.lustre.org
> http://lists.lustre.org/listinfo.cgi/lustre-discuss-lustre.org