Hello Folks,
A while back (say 3 weeks ago) we started noticing extremely high loads
(load avg around 300 at times) on our OSSs when in production and serving IO.
This cluster was, at the time, on 1.8.2 (we have since upgraded to 1.8.4 but
the problem remains). The load increases fairly predictably as clients
generate IO but even 2 clients can produce a load avg above 5.00. An identical
file system of ours does not exhibit this behavior (sticks below load avg 1.00
under even the heaviest IO load). I've looked around bugzilla and haven't
found anything. We've disabled heartbeat on the off-chance that was generating
the load (it's not), we've attempted using a different client transport
(o2ib->tcp), this did not solve the issue. There doesn't appear to be any
specific non-kernel thread causing the high-load. The only info in
dmesg/syslog pertains to sporadic client evictions or sporadic slow setattr due
to heavy IO load (we've since tuned the number of OST threads). We're basically
out of ideas to try.
As reference, this is a 1 MDS/4 OSS cluster backed by a DDN 9900 couplet (15
tiers, 1:1 lun mapping) running the lustre.org rpm build kernel for 1.8.4. The
MDS/OSSs are Dell R710s and the MDT is a Dell MD1000. Is this a common problem
or should a bug be filed? Any info available upon request. Thanks for your
time.
----------------
John White
High Performance Computing Services (HPCS)
(510) 486-7307
One Cyclotron Rd, MS: 50B-3209C
Lawrence Berkeley National Lab
Berkeley, CA 94720
_______________________________________________
Lustre-discuss mailing list
[email protected]
http://lists.lustre.org/mailman/listinfo/lustre-discuss
