[Lustre-discuss] OST Pools

[John White]

Hello Folks,
So we're planning on upgrading to 1.8 to take advantage of OST
Pools. Namely, we have an existing filesystem running off DDN 9900s
and are getting some new arrays of a different (known slower)
hardware. The aim is to create an (almost) institutional file system
where new groups can just purchase OSTs and go. So from what
documentation I can find, the process for this would appear to be:
-create OSTs as you normally would
-create a new OST pool (lctl pool_new [fsname].[newpoolneame]
-add new OSTs to new OST Pool (lctl pool_add [fsname].[newpoolname]
[newostuids]
-create a new directory within the existing file system to associate
with new pool (lfs setstripe [newdirectory] -p [newpoolname]

and... that should be all, right?.. As long as I'm careful with the
writeconf command going forward, I should be fairly safe with the
newfangled pool stuff?
----------------
John White
High Performance Computing Services (HPCS)
(510) 486-7307
One Cyclotron Rd, MS: 50B-3209C
Lawrence Berkeley National Lab
Berkeley, CA 94720

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[Andreas Dilger]

On Oct 05, 2009 09:47 -0700, John White wrote:
> So we're planning on upgrading to 1.8 to take advantage of OST
> Pools. Namely, we have an existing filesystem running off DDN 9900s
> and are getting some new arrays of a different (known slower)
> hardware. The aim is to create an (almost) institutional file system
> where new groups can just purchase OSTs and go. So from what
> documentation I can find, the process for this would appear to be:
> -create OSTs as you normally would
> -create a new OST pool (lctl pool_new [fsname].[newpoolneame]
> -add new OSTs to new OST Pool (lctl pool_add [fsname].[newpoolname]
> [newostuids]
> -create a new directory within the existing file system to associate
> with new pool (lfs setstripe [newdirectory] -p [newpoolname]
>
> and... that should be all, right?.. As long as I'm careful with the
> writeconf command going forward, I should be fairly safe with the
> newfangled pool stuff?

Yes, that should be all that is needed. Note that if you are still
using 1.6.x clients you should wait for the 1.8.1.1 release, as you
will otherwise have some interop problems on files that were created
within the pool.

Note that the "lfs setstripe" above will cause new files/directories
in "newdirectory" to be created in "newpoolname", but there isn't
anything preventing a user from selecting a different pool if they
know how to use "lfs setstripe".

Also, any new files/directories created outside of "newdirectory" will
use the default pool, which includes all OSTs.

Cheers, Andreas
--
Andreas Dilger
Sr. Staff Engineer, Lustre Group
Sun Microsystems of Canada, Inc.