[gpfsug-discuss] Lost disks

[Jonathan Buzzard]

On Thu, 2017-07-27 at 16:18 +0200, Uwe Falke wrote:

> "Just doing something" makes things worse usually. Whether a 3rd
> party tool knows how to handle GPFS NSDs can be doubted (as long as it
> is not dedicated to that purpose). 

It might usually, but IBM have *ALREADY* given up in this case and told
the customer their data is toast. Under these circumstances other than
wasting time that could have been spent profitably on a restore it is
*IMPOSSIBLE* to make the situation worse.

[SNIP]

> It seems not a bad idea to set aside the NSD headers of your NSDs  in a 
> back up :-)
> And also now: Before amending any blocks on your disks, save them!
> 

It's called NSD v2 descriptor format, so rather than use raw disks they
are in a GPT partition, and for good measure a backup copy is stored at
the end of the disk too.

Personally if I had any v1 NSD's in a file system I would have a plan
for a series of mmdeldisk/mmcrnsd/mmadddisk to get them all to v2 sooner
rather than later.

JAB.

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