An update. We were able to recover our filesystem (minus the two days between
when the ZFS swap occurred and when we detected it and shut down the
filesystem). Simply promoting the cloned ZFS volume (which was really our
primary volume) and cleaning up the snapshot and clone got us back to
First thing, if you haven't already done so, would be to make a separate "dd"
backup of the ldiskfs MDT(s) to some external storage before you do anything
else. That will give you a fallback in case whatever changes you make don't
work out well.
I would also suggest to contact the ZFS mailing
A quick follow up. I thought an lfsck would only clean up (i.e. remove
orphaned MDT and OST objects) but it appears this might have a good shot at
repairing the file system – specifically, recreating the MDT objects with the
--create-mdtobj option. We have started this command:
Hi everyone,
We ran into a problem with our lustre filesystem this weekend and could use a
sanity check and/or advice on recovery.
We are running on CentOS 7.9, ZFS 2.1.4 and Lustre 2.14. We are using ZFS
OST’s but and an ldiskfs MDT (for better MDT performance). For various
reasons, the
