[gpfsug-discuss] Restriping GPFS Metadata

[Jonathan Buzzard]

On Thu, 2015-12-10 at 13:46 +0000, Luke Raimbach wrote:
> Hi All,
> 
> Some years ago I remember adding more metadata SSDs to a GPFS 3.5 file
> system (system pool with MD only disks) and then trying to restripe the
> metadata.
> 
> It didn’t work and I asked about it, only to discover that metadata
> doesn't get restriped.
> 
> Has this changed? Does it matter if MD is not restriped? I ask because
> I'll probably want to add more MD SSDs to a new system in the near
> future.
> 

Hum, that is I believe inaccurate. Metadata does get restriped in at
least the case where you move it from one set of disks to another set of
disks. It should also get restriped it you change the replication
factor. However I am pretty sure that it gets restriped without the
necessity to move it from one set of disks to another as well.

The caveat is that you cannot restripe *just* the metadata. You have to
restripe the whole file system... Or at least that used to be the case
and maybe why you have the idea the metadata didn't get restriped.
Whether this has changed in 4.x is another matter that perhaps someone
from IBM can answer.

JAB.

-- 
Jonathan A. Buzzard                 Email: jonathan (at) buzzard.me.uk
Fife, United Kingdom.