[gpfsug-discuss] Restriping GPFS Metadata

[Luke Raimbach]

> 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.

Ah yes I remember now. I was wanting to rebalance the disk usage (rather than move on to new disks - I knew this would work obviously). You're right in that I had to restripe the whole file system and this would have taken forever, so I just didn't bother!

Cheers
Luke.
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