[Lustre-discuss] Recovering a reformatted OST

[Dilger, Andreas]

On 2015/01/29, 12:34 PM, "Bob Ball" <ball at umich.edu> wrote:

>This is Lustre 2.1.6.
>
>I did a dumb thing.  I reformatted a drained OST BEFORE I saved off
>appropriate data to re-establish it at its old index.  I don't know what
>I was thinking?  The files that I would normally restore are,
>LAST_ID
>last_rcvd
>mountdata
>umt3-OST0020
>
>I know how to recreate the correct LAST_ID.  And, as this happened over
>a year ago on this same OST, I have old copies still of each of the
>others.  I know that "mountdata" is created when I created the lustre
>file system, so I would guess I can just continue to use that file.
>
>My question, can I simply re-use these other, old file copies when I am
>ready to once again put a Lustre file system on this volume?

The mountdata file should be the same.  The last_rcvd file will be
recreated during mount if it is missing, though the old one could also be
used.  The umt3-OST0020 config file would be recreated with a --writeconf,
but it may also be created automatically during mount if missing (it is an
OST-local copy of the MGS file of the same name so the OST can mount even
if the MGS is offline).

Cheers, Andreas
-- 
Andreas Dilger

Lustre Software Architect
Intel High Performance Data Division