[gpfsug-discuss] Restriping GPFS Metadata

Buterbaugh, Kevin L Kevin.Buterbaugh at Vanderbilt.Edu
Thu Dec 10 14:04:29 GMT 2015


Hi All,

We recently moved all of our metadata off of spinning hard drives to SSD’s via restriping.  You can restripe only a specific pool with the “-P” option, so if you have only your metadata disks in the system pool then you can definitely do this…

Kevin, who does not work for IBM… ;-)

> On Dec 10, 2015, at 7:56 AM, Jonathan Buzzard <jonathan at buzzard.me.uk> wrote:
> 
> 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.
> 
> 
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