[gpfsug-discuss] Lost disks

[Jonathan Buzzard]

On Thu, 2017-07-27 at 07:28 -0400, RICHARD RUPP wrote:
> If you are under IBM support, leverage IBM for help. A third party
> utility has the possibility of making it worse. 
> 

The chances of recovery are slim in the first place from this sort of
problem. At least with v1 NSD descriptors. Further IBM have *ALREADY*
told him the data is lost, I quote 

    But in their PMR they were told that all that data is lost now
    and that the disk headers didn’t appear as GPFS disk headers. 

So in this scenario you have little to loose trying something because
you are now on your own. Worst case scenario is that whatever you try
does not work, which leave you no worse of than you are now. Well apart
from lost time for the restore, but you might have started that already
to somewhere else.

I was once told by IBM (nine years ago now) that my GPFS file system was
caput and to arrange a restore from tape. At which point some fiddling
by myself fixed the problem and a 100TB restore was no longer required.
However this was not due to overwritten NSD descriptors. When that
happened the two file systems effected had to be restored. Well
bizarrely one was still mounted and I was able to rsync the data off. 

However the point is that at this stage fiddling with third party tools
is the only option left.

JAB.

-- 
Jonathan A. Buzzard                         Tel: +44141-5483420
HPC System Administrator, ARCHIE-WeSt.
University of Strathclyde, John Anderson Building, Glasgow. G4 0NG