[Linux-cluster] Cluster Project FAQ - GFS tuning section]

[Jon Erickson]

On 1/23/07, David Teigland <teigland at redhat.com> wrote:
> On Tue, Jan 23, 2007 at 08:39:32AM -0500, Wendell Dingus wrote:
> > I don't know where that breaking point is but I believe _we've_ stepped
> > over it.
>
> The number of files in the fs is a non-issue; usage/access patterns is
> almost always the issue.
>
> > 4-node RHEL3 and GFS6.0 cluster with (2) 2TB filesystems (GULM and no
> > LVM) versus
> > 3-node RHEL4 (x86_64) and GFS6.1 cluster with (1) 8TB+ filesystem (DLM
> > and LVM and way faster hardware/disks)
> >
> > This is a migration from the former to the latter, so quantity/size of
> > files/dirs is mostly identical. Files being transferred from customer
> > sites to the old servers never cause more than about 20% CPU load and
> > that usually (quickly) falls to 1% or less after the initial xfer
> > begins. The new servers run to 100% where they usually remain until the
> > transfer completes. The current thinking as far as reason is the same
> > thing being discussed here.
>
> This is strange, are you mounting with noatime?  Also, try setting this on
> each node before it mounts gfs:
>
> echo "0" > /proc/cluster/lock_dlm/drop_count
What does this do?


>
> Dave
>
> --
> Linux-cluster mailing list
> Linux-cluster at redhat.com
> https://www.redhat.com/mailman/listinfo/linux-cluster
>


-- 
Jon