Hi
When you are on RHEL4.5 then I highly suggest you to use
the new glock_purge Parameter for every gfs Filesystem add to
/etc/rc.local
-------
gfs_tool settune / glock_purge 50
gfs_tool settune /scratch glock_purge 50
-------
gfs_tool settune /scratch glock_purge 50
-------
also this Parameter has to set new on every mount. That
mean when you umount it and then mount it again, run the /etc/rc.local again,
otherway the parameter are gone!
maybe also checkout this page --> http://www.open-sharedroot.org/Members/marc/blog/blog-on-gfs/glock-trimming-patch
mike
From: linux-cluster-bounces@xxxxxxxxxx [mailto:linux-cluster-bounces@xxxxxxxxxx] On Behalf Of Claudio Tassini
Sent: Montag, 10. September 2007 13:19
To: linux clustering
Subject: GFS: drop_count and drop_period tuning
I have a four-nodes GFS cluster on RH 4.5 (last versions, updated
yesterday). There are three GFS filesystems ( 1 TB, 450 GB and 5GB), serving
some mail domains with postfix/courier imap in a "maildir" configuration.
As you can suspect, this is not exactly the best for GFS: we have a lot
(thousands) of very small files (emails) in a very lot of directories. I'm
trying to tune up things to reach the best performance. I found that tuning the
drop_count parameter in /proc/cluster/lock_dlm/drop_period , setting it to a
very large value (it was 500000 and now, after a memory upgrade, I've set it to
1500000 ), uses a lot of memory (about 10GB out of 16 that I've installed in
every machine) and seems to "boost" performance limiting the iowait CPU usage.
The bad thing is that when I umount a filesystem, it must clean up all that
locks (I think), and sometimes it causes problems to the whole cluster, with the
other nodes that stop writes to the filesystem while I'm umounting on one node
only.
Is this normal? How can I tune this to clean memory faster when I umount
the FS? I've read something about setting more gfs_glockd daemons per fs with
the num_glockd mount option, but it seems to be quite deprecated because it
shouldn't be necessary..
--
Claudio Tassini
-- Linux-cluster mailing list Linux-cluster@xxxxxxxxxx https://www.redhat.com/mailman/listinfo/linux-cluster
