[Lustre-discuss] mixing server versions

[Andreas Dilger]

On 2010-09-15, at 12:36, Brock Palen wrote:
> We have a filesystem that we can't take down for a while to upgrade the oss's they are running 1.6.x  we do have a need to quickly add some storage to it, and thus the new server would have 1.8.x   
> 
> Is there any problems with this?   I know 1.6.x isn't supported anymore and we would like to move everything to 1.8 soon but we are in a bind for the moment.
> 
> Is our only (safe) option to load 1.6.x on the new server also and wait till we can shutdown the filesystem?

We do test upgrade compatibility between 1.6.latest and 1.8.y when making a new 1.8.y release.  We don't do a full x * y compatibility testing for all 1.6.x and 1.8.y releases, with all combinations of OSS, MDS, client releases, nor do we run with different versions on the MDS and OSS for extended periods of time.

The safest path would be to keep your new OSTs with the same 1.6.x release as your other OSTs, and then upgrade them later when you are ready to do them all.

That said, I wouldn't _expect_ problems if you run some OSTs with 1.8 for a while, but depending on which two releases you have there could be some issues.

Cheers, Andreas
--
Andreas Dilger
Lustre Technical Lead
Oracle Corporation Canada Inc.