[Lustre-discuss] reorder OSTs?

[Liam Forbes]

I just built a lustre filesystem, and it appears to be working fine.
However, I think I'd like to reorder the OSTs in order to spread the
work across the OSSes better.  Is this something I can do on the fly,
or do I have to rebuild the filesystem in a different order?  If the
latter, I need to do that now before we put any users on it.  Or maybe
the ordering doesn't matter?

package:~$ /usr/sbin/lctl get_param osc.*.ost_conn_uuid
osc.wrkdir10-OST0000-osc-ffff810bf4784c00.ost_conn_uuid=10.54.128.123 at tcp
osc.wrkdir10-OST0001-osc-ffff810bf4784c00.ost_conn_uuid=10.54.128.123 at tcp
osc.wrkdir10-OST0002-osc-ffff810bf4784c00.ost_conn_uuid=10.54.128.123 at tcp
osc.wrkdir10-OST0003-osc-ffff810bf4784c00.ost_conn_uuid=10.54.128.123 at tcp
osc.wrkdir10-OST0004-osc-ffff810bf4784c00.ost_conn_uuid=10.54.128.124 at tcp
osc.wrkdir10-OST0005-osc-ffff810bf4784c00.ost_conn_uuid=10.54.128.124 at tcp
osc.wrkdir10-OST0006-osc-ffff810bf4784c00.ost_conn_uuid=10.54.128.124 at tcp
osc.wrkdir10-OST0007-osc-ffff810bf4784c00.ost_conn_uuid=10.54.128.124 at tcp
osc.wrkdir10-OST0008-osc-ffff810bf4784c00.ost_conn_uuid=10.54.128.125 at tcp
osc.wrkdir10-OST0009-osc-ffff810bf4784c00.ost_conn_uuid=10.54.128.125 at tcp
osc.wrkdir10-OST000a-osc-ffff810bf4784c00.ost_conn_uuid=10.54.128.125 at tcp
osc.wrkdir10-OST000b-osc-ffff810bf4784c00.ost_conn_uuid=10.54.128.125 at tcp
osc.wrkdir10-OST000c-osc-ffff810bf4784c00.ost_conn_uuid=10.54.128.126 at tcp
osc.wrkdir10-OST000d-osc-ffff810bf4784c00.ost_conn_uuid=10.54.128.126 at tcp
osc.wrkdir10-OST000e-osc-ffff810bf4784c00.ost_conn_uuid=10.54.128.126 at tcp
osc.wrkdir10-OST000f-osc-ffff810bf4784c00.ost_conn_uuid=10.54.128.126 at tcp
osc.wrkdir10-OST0010-osc-ffff810bf4784c00.ost_conn_uuid=10.54.128.127 at tcp
osc.wrkdir10-OST0011-osc-ffff810bf4784c00.ost_conn_uuid=10.54.128.127 at tcp
osc.wrkdir10-OST0012-osc-ffff810bf4784c00.ost_conn_uuid=10.54.128.127 at tcp
osc.wrkdir10-OST0013-osc-ffff810bf4784c00.ost_conn_uuid=10.54.128.127 at tcp
osc.wrkdir10-OST0014-osc-ffff810bf4784c00.ost_conn_uuid=10.54.128.128 at tcp
osc.wrkdir10-OST0015-osc-ffff810bf4784c00.ost_conn_uuid=10.54.128.128 at tcp
osc.wrkdir10-OST0016-osc-ffff810bf4784c00.ost_conn_uuid=10.54.128.128 at tcp
osc.wrkdir10-OST0017-osc-ffff810bf4784c00.ost_conn_uuid=10.54.128.128 at tcp
osc.wrkdir10-OST0018-osc-ffff810bf4784c00.ost_conn_uuid=10.54.128.129 at tcp
osc.wrkdir10-OST0019-osc-ffff810bf4784c00.ost_conn_uuid=10.54.128.129 at tcp
osc.wrkdir10-OST001a-osc-ffff810bf4784c00.ost_conn_uuid=10.54.128.129 at tcp
osc.wrkdir10-OST001b-osc-ffff810bf4784c00.ost_conn_uuid=10.54.128.129 at tcp
osc.wrkdir10-OST001c-osc-ffff810bf4784c00.ost_conn_uuid=10.54.128.130 at tcp
osc.wrkdir10-OST001d-osc-ffff810bf4784c00.ost_conn_uuid=10.54.128.130 at tcp
osc.wrkdir10-OST001e-osc-ffff810bf4784c00.ost_conn_uuid=10.54.128.130 at tcp
osc.wrkdir10-OST001f-osc-ffff810bf4784c00.ost_conn_uuid=10.54.128.130 at tcp

package:~$ sudo /usr/sbin/lctl lustre_build_version
Lustre version: jenkins-wc1--PRISTINE-2.6.18-238.19.1.563g0000.el5
lctl   version: jenkins-wc1--PRISTINE-2.6.18-238.19.1.563g0000.el5
package:~$ rpm -qa | grep lustre
lustre-client-1.8.6-wc1_2.6.18_238.12.1.el5
lustre-client-source-1.8.6-wc1_2.6.18_238.12.1.el5
package:~$ uname -a
Linux package 2.6.18-238.19.1.563g0000.el5 #1 SMP Fri Jul 15 20:26:36
EDT 2011 x86_64 x86_64 x86_64 GNU/Linux
package:~$ cat /etc/redhat-release
Red Hat Enterprise Linux Server release 5.7 (Tikanga)

Thanks for any input!

-- 
Regards,
-liam

-There are uncountably more irrational fears than rational ones. -P. Dolan
Liam Forbes       HPC Systems Analyst,      HPC&S Group Leader,      CISSP
ARSC, U of AK, Fairbanks   lforbes at arsc.edu 907-450-8618 fax: 907-450-8605