[Lustre-discuss] multiple runs of lfsck with different options using same mds and ost db's

[Andreas Dilger]

On Aug 24, 2009  19:14 +0530, rishi pathak wrote:
> Can lfsck be run multiple times using different set of options (options like
> -l -c and -d ) using the same set of mds and ost db's.
> For e.g what to expect if lfsck is run for coherence check after a MDS crash
> in the following order
> 
> 2.lfsck to backup orphaned objects (-l option)
> 3.lfsck to delete  orphaned objects (will it find any after backup)

Running both of these will cause problems.  The "-l" option will link
the objects into files in the lost+found directory, but then "-d" will
delete the objects, so now you have files in lost+found that are
referencing non-existent objects.

> 4.lfsck to  create missing OST objects MDS inodes (-c option).
> 
> In all the above runs same mdsdb and ostds's were used.
> Is it advisable/mandatory to recreate mdsdb and ostdb's again after a fix is
> done using lfsck.

Yes.

> Can all the tasks mentioned above be accomplished in a single run (i.e. can
> -l -d -c be specified together)?

They can, though specifying both "-l" and "-d" will result in "-d" taking
preference.

Cheers, Andreas
--
Andreas Dilger
Sr. Staff Engineer, Lustre Group
Sun Microsystems of Canada, Inc.