ZFS system unresponsive

[Tim Bishop]

Hi Jeremy,

On Sun, Mar 13, 2011 at 11:07:59AM -0700, Jeremy Chadwick wrote:
> I'm snipping the statistics that instead people can read via the mailing
> list archive URL:
> 
> http://lists.freebsd.org/pipermail/freebsd-fs/2011-February/010796.html
> 
> On Sun, Mar 13, 2011 at 04:44:30PM +0000, Tim Bishop wrote:
> > I did the upgrade to 8-STABLE and it didn't help. I'm still seeing the
> > same issue.
> > 
> > Someone else in another thread mentioned about graphing the zfs-stats
> > output with munin, so I thought I'd give that a whirl. Here are the
> > results:
> > 
> > (static snapshot of data so it doesn't change between when I write this
> > and when somebody reads it)
> > 
> > http://www.bishnet.net/tim/tmp/munin/carrick/carrick/index.html
> > 
> > This slow down is triggered by the tarsnap backups I run each day. They
> > start about 01:15 (in the same timezone as the graphs) and finished at
> > around 11:15 after I poked it. It slows down when processing my Maildir
> > folders, but doesn't actually stop - it's processing a single file every
> > couple of seconds.
> 
> The below may be informational to you, or at least give you something to
> ponder.  It may not be the problem you're experiencing, so I don't want
> to divert you from your efforts.  Please keep that in mind when reading
> the below.

[snip ZFS and Maildir notes]

Thanks for your reply. I'll check those details over to see if there's
anything of relevance. But I just wanted to point out that this doesn't
happen all the time. It happens maybe 1 night in 5 when backing up. So
it doesn't seem like it's an inherent issue with Maildir on ZFS.

But yes, I do agree Maildir on ZFS is poor. I also have a
Maildir+Solaris+NFS setup at work :-)

Tim.

-- 
Tim Bishop
http://www.bishnet.net/tim/
PGP Key: 0x5AE7D984