* Mark Moseley <moseleym...@gmail.com>: > On Wed, Dec 8, 2010 at 3:03 PM, Timo Sirainen <t...@iki.fi> wrote: > > On 8.12.2010, at 22.52, Cor Bosman wrote: > > > >> 1 server with service_count = 0, and src/imap/main.c patch > > > > By this you mean service_count=0 for both service imap-login and service > > imap blocks, right? > > > > > > Speaking from my own experience, the system loads on our dovecot boxes > went up *substantially* when we upgraded kernels from 2.6.32.x and > 2.6.33.x to newer ones (late 2.6.35.x and 2.6.36 -- haven't tried > 2.6.36.1 yet). But I also saw loads on all sort of other types of > boxes grow when moved to 2.6.35.x and 2.6.36, so it's not necessarily > dovecot-related. Though you've got plenty to choose from between > 2.6.27.x and up.
We're on 2.6.32 and the load only goes up when I change dovecot (not when I change the kernel, which I didn't do so far) > Getting 'imap-login' and 'pop3-login' set to service_count=0 and > 'pop3' and 'imap' set to service_count=1000 (as per Timo's suggestion) > helped keep the boxes from spinning into oblivion. To reduce the > enormous amount of context switches, I've got 'pop3's client_limit set > to 4. I played around with 'imap's client_limit between 1 and 5 but > haven't quite found the sweet spot yet. pop3 with client_limit 4 seems > to work pretty good. That brought context switches down from > 10,000-30,000 to sub-10,000. Interesting. Would that spawn a lot of pop3 processes? On the other hand, almost nobody is using pop3 here -- Ralf Hildebrandt Geschäftsbereich IT | Abteilung Netzwerk Charité - Universitätsmedizin Berlin Campus Benjamin Franklin Hindenburgdamm 30 | D-12203 Berlin Tel. +49 30 450 570 155 | Fax: +49 30 450 570 962 ralf.hildebra...@charite.de | http://www.charite.de
