--On October 19, 2006 11:25:07 PM +0200 Marten Lehmann <lehmann@xxxxxx>
wrote:
Hello,
Uhm... LA of 30 is very high. What OS? I assume Linux, vmstat 5 will
tell you where you're hitting the wall, but unless you've got an 8 CPU
machine LA 30 is rather quite high. Linux LA is a measurement of
processes blocked on I/O, processes running and processes waiting to run
on a CPU.
yes, Linux (2.6.9, RHEL4):
Looking at taht i'd say you're VERY badly CPU bound. a simple dd/cp
doesn't do anything to the mail but IMAP ops will require some CPU
work....Cyrus also will probably be forcing syncs but your I/O load doesn't
look that high (my mfe's run more I/O and they're not storing any mail,
just logs and temporary files for virus/spam scanning heh, and they only
have a little IDE HDD each)
the numebrs in the procs->r column indicate you've got a lot of processes
vying for CPU time. the b column indicates you've got a little bit of
blocking going on. Processes in the 'D' state may show up in ps or top
output (doubtfully top unless you change the default sort).
I'd guess you're being CPU bound and cyrus is probably running (usually
does by default) at a bit lower priority than your interactive cp
operations. 2.6 kernel scheduler does a lot of weird stuff if it
determines you're interactive, and then tends to give you priority over
daemons. it's very non-deterministic, but I don't think you're running
into this. quite likely some inefficiencies in the cyrus code (or
intentional backoffs?) but mostly just being CPU bound. I know our MBEs
can generally scp or rsync quite a bit faster than they can perform a
XFER/RENAME command that moves between mail store servers (IE MURDER host
to MURDER host).
----
Cyrus Home Page: http://cyrusimap.web.cmu.edu/
Cyrus Wiki/FAQ: http://cyrusimap.web.cmu.edu/twiki
List Archives/Info: http://asg.web.cmu.edu/cyrus/mailing-list.html
