[lustre-discuss] problem after upgrading 2.10.4 to 2.12.4

[Franke, Knut]

Am Dienstag, den 23.06.2020, 20:03 +0000 schrieb Hebenstreit, Michael:
> Is there any way to stop the scans on the OSTs?

Yes, by re-mounting them with -o noscrub. This doesn't fix the issue
though.

> Is there any way to force the file system checks?

As shown in your second mail, the scrubs are already running.
Unfortunately, they don't (as of Lustre 2.12.4) fix the issue.

> Has anyone found a workaround for the FID sequence errors?

Yes, see the script attached to LU-13392. In short:

0. Make sure you have a backup. This might eat your lunch and fry your
cat for afters.
1. Enable the canmount property on the backend filesystem. For example:
   [oss]# zfs set canmount=on mountpoint=/mnt/ostX ${fsname}-ost/ost
2. Mount the target as 'zfs'. For example:
   [oss]# zfs mount ${fsname}-ost/ost
3. update_25_objects /mnt/ostX
4. unmount and remount the OST as 'lustre'

This will rewrite the extended attributes of OST objects created by
Lustre 2.4/2.5 to a format compatible with 2.12.

> Can I downgrade from 2.12.4 to 2.10.8 without destroying the FS?

We've done this successfully, but again - no guarantees.

> Has the error described in https://jira.whamcloud.com/browse/LU-13392
>  been fixed in 2.12.5?

I don't think so.

Cheers,
Knut
-- 
Knut Franke
Systems Engineer
science + computing ag
Teamline: +49 7071 94 57 680
Hagellocher Weg 73
D-72070 Tübingen
Website: https://www.atos.net/