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? Thanks! Brock Palen www.umich.edu/~brockp Center for Advanced Computing brockp at umich.edu (734)936-1985
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.
On 2010-09-15, at 13:32, Brock Palen wrote:> Thanks that is great to know. Is there much risk to try with 1.8 and then back off to 1.6 if there are issues? Risk of data loss?We do not test/support formatting at a higher Lustre version, and then downgrading below the original version used for formatting. With 1.6->1.4 this definitely did not work, though I''m not sure if there are specific incompatibilities between 1.8->1.6. Cheers, Andreas -- Andreas Dilger Lustre Technical Lead Oracle Corporation Canada Inc.
On Wednesday, September 15, 2010, Andreas Dilger wrote:> On 2010-09-15, at 13:32, Brock Palen wrote: > > Thanks that is great to know. Is there much risk to try with 1.8 and > > then back off to 1.6 if there are issues? Risk of data loss? > > We do not test/support formatting at a higher Lustre version, and then > downgrading below the original version used for formatting. With 1.6->1.4 > this definitely did not work, though I''m not sure if there are specific > incompatibilities between 1.8->1.6.I go back and forth from 1.8 to 1.6 quite often. The only thing to take care about is to make sure the MDS does not get the extents flag if ext4-ldiskfs is used. I think only beginning with 1.8.4 that is ensured by Lustre itself. Cheers, Bernd -- Bernd Schubert DataDirect Networks