[Ocfs2-users] slowdown - fragmentation?

[Brian Kroth]

Brian Kroth <bpkroth at gmail.com> 2010-04-26 09:17:
> Hello all,
> 
> I've got a moderately active mail system running on OCFS2.  It's been on
> fresh volume for about 9 months now, however only ever with one node
> active at a time.  For the most part it's been very happy, however
> recently we started experiencing very noticeable and periodic but short
> lived slowdowns.  From all of the graphs and measurements I've been
> doing the IO system seems bored (not much more than ~200 IOPS even, and
> typically less on a 14 disk raid 50 with 15K disks).  We haven't changed
> anything recently and I'm having trouble nailing down the cause.  Given
> all the talk about ENOSPC and fragmentation of late it's growing on my
> list of worries.  Can someone please take a look at my stat_sysdir
> output and give me a quick opinion of whether or not they think that
> might be and issue?
> 
> Thanks for your help,
> Brian
> 
> 
> We're running Debian Lenny with a 2.6.30 kernel in VMWare ESX 4.
> 
> # dpkg -l | grep -i ocfs2
> ii  ocfs2-tools                                             1.4.2-1 

First, sorry for spamming everyone's mailbox by attaching that dump last
time.  I should have posted it somewhere.

Unfortunately, we've gotten confirmation that we hit the infamous ENOSPC
bug [1] in error messages stating the inability to store new mail
messages.

We performed the recommended reduction in slots from 8 to 4 and things
are temporarily up and running again.  However, I'm curious if you have
any thoughts on how much time or # of files we've bought ourselves by
doing this.  Ideally we'd like to be able to hold out for another month
when there's a mandatory "holiday" so that no you can use the system
anyways before we do our total overhaul fix.

Here's the results of two stat_sysdir.sh dumps.
http://cae.wisc.edu/~bpkroth/public/ocfs2/

Thanks very much,
Brian

[1] http://oss.oracle.com/bugzilla/show_bug.cgi?id=1189
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