[Lustre-discuss] Recovering a failed OST

[Bob Ball]

I need to completely remake a failed OST.  I have done this in the past, 
but this time, the disk failed in such a way that I cannot fully get 
recovery information from the OST before I destroy and recreate.  In 
particular, I am unable to recover the LAST_ID file, but successfully 
retrieved the last_rcvd and CONFIGS/* files.

mount -t ldiskfs /dev/sde /mnt/ost
pushd /mnt/ost
cd O
cd 0
cp -p LAST_ID /root/reformat/sde

The O directory exists, but it is empty.  What can I do concerning this 
missing LAST_ID file?  I mean, I probably have something, somewhere, 
from some previous recovery, but that is way, way out of date.

My intent is to recreate this OST with the same index, and then put it 
back into production.  All files were moved off the OST before reaching 
this state, so nothing else needs to be recovered here.

Thanks,
bob