[Lustre-discuss] Data corruption?

Brian J. Murrell Brian.Murrell at Sun.COM
Fri Mar 27 08:52:37 PDT 2009


On Fri, 2009-03-27 at 10:21 -0500, Nirmal Seenu wrote:
> 
> It was different partitions on the same machine. I did the following 
> from a LVM snapshot

So you took a copy of an LVM snapshot of an MDT on a live filesystem and
then replaced the MDT that you took the snapshot of with the copy on the
new partition?

> of the old MDT which got mounted as ldiskfs
> 
> (tar --sparse -cf - . | ( cd /mnt/new-mdt; tar -xf -)) &

So you didn't make a back up of the extended attributes too?

> and then brought the entire Lustre filesystem down and did a final rsync 
> after mounting both the old and new MDT as ldiskfs:
> 
> rsync -aSv /mnt/mdt/ /mnt/new-mdt

Again, no extended attribute copying.

> and then I did a getfattr, setfattr and "rm OBJECTS/* CATALOGS"

Hrm.  Whilte it seems that you might have done the right thing it's not
clear from your brief description that you did the right things.  Did
you use the process in the operations manual as a model for your
process?

> cart_wengen.odd_even.txt is a new file that was created by a user after 
> the lustre filesystem was brought online after performing a lfsck. i.e. 
> I don't have an entry for cart_wengen.odd_even.txt in lfsck output, but 
> the "ls -l" output lists the same file with ?.

Well, sounds like objects are getting removed or going missing by some
means.

> Not much I/O has happened since the last time I did a lfsck(last night). 
> Would another lfsck actually help in fixing this problem?

It's difficult to tell, as it's not clear why you are still getting
errors after your last lfsck.  It certainly could not hurt if your goal
is to just get the MDT and OSTs back in sync.

b.

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