Lustre discuss - Mar 2008 - OST balancing (1.6) question

Hi,

We have a mix of 1.4 and 1.6 clients and so when we recently expanded one of our
filesystems we had to downgrade to 1.4 on the servers and do a write_conf to
record the new config. After upgrading the servers back to 1.6 both 1.4 and 1.6
clients could see the new OSS fine. My question is if we have 1.6 clients will
they try to balance OST space no matter what or do they have to mount the
filesystem using the "mgs" (1.6) mount method to enable this feature?
If they use the old (1.4) mount command format will they just round-robin writes
like a 1.4 client would?

Daire

On Mar 04, 2008  09:18 +0000, Daire Byrne wrote:
> We have a mix of 1.4 and 1.6 clients and so when we recently expanded
> one of our filesystems...
> My question is if we have 1.6 clients will they try to balance OST space
> no matter what or do they have to mount the filesystem using the
"mgs"
> (1.6) mount method to enable this feature? If they use the old (1.4) mount
> command format will they just round-robin writes like a 1.4 client would?
The space balancing is purely a feature of the MDS, the clients have
nothing to do with object allocation in 1.4 or 1.6, so you should be
fine if you are running any version of Lustre 1.6 on the MDS.

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