On Wed, 23 Jan 2013, francis picabia wrote: > Here are more stats. Do these look average for performance? > It is difficult to understand why the system was working with few > load spikes before. > > A mailman mailing list sends 10kbyte message to 4000 > users having accounts on this cyrus system. If I > grep "Delivered" in the maillog by the minute I can > see how fast the messages are stored. > > e.g.: > # grep Delivered /var/log/maillog | grep 'Jan 23 10:37' | wc -l > 696 > > That is the best. This peak event pushed the load to 14 > for 12 minutes, where it averages 604 messages > delivered to cyrus mailboxes per minute. Is that > reasonable for maximum delivery rate? > > I've also backed out the change (yesterday) to > /sys/block/sda/queue/nr_requests > I think it was pushing the load higher and there is no advantage > in my hardware (SAS with Perc 5/i Raid 5 over 4 disk) > to run with a low value for nr_requests. You can certainly achieve higher delivery rates, but that all depends on your underlying hardware and how you have partitioned your system. Why don't you start running "iostat -x 5" on the system? Leave this running to give you an idea of the baseline behavior and then look at it during periods of high load. I suspect you will see that your svctm and %util will go up dramatically when a large number of messages are being delivered. But, let's not make decisions based on assumptions! :) On my Cyrus Murder frontends (3 of them), I have limited LMTP connections to 25 in cyrus.conf: lmtp cmd="/usr/local/cyrus/bin/lmtpproxyd" listen="lmtp" proto="tcp4" prefork=0 maxchild=25 This prevents our mail relays (Postfix) from opening too many simultaneous LMTP connections, which can cause too much I/O contention. Take a look during your periods of high load to see how many lmtpd processes are running. You may want to limit the number. Andy ---- Cyrus Home Page: http://www.cyrusimap.org/ List Archives/Info: http://lists.andrew.cmu.edu/pipermail/info-cyrus/ To Unsubscribe: https://lists.andrew.cmu.edu/mailman/listinfo/info-cyrus
