dovecot - Jun 2009 - enourmous amount of disc writes

Hi List,
on my mailserver (exim4, dovecot 1.0.0, postgresql, ubuntu dapper, about 
500 users) I record an enourmous amount of disc writes (up to 18000 
blocks written each second) in the time where most of users are active.
This IO activity causes wait-states on the disc interface (RAID5) and 
finally slows down my mailmachine. Is there a explanation for these disc 
writes respectively is there a possibility to minimize this activity. 
Stopping Dovecot on this machine causes stopping most of the disc activity.

Regards
Rainer Sigl


-- 
-----------------
Rainer Sigl,                      | email: sigl at mpe.mpg.de
MPI f. extraterrestrische Physik, | phone: +49 (89) 30000-3557
Postfach 1312,                    | fax:   +49 (89) 30000-3569
D-85741 Garching, Germany         | web:   http://www.mpe.mpg.de/~sigl/
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Rainer Sigl schrieb:
> Hi List,
> on my mailserver (exim4, dovecot 1.0.0, postgresql, ubuntu dapper, about
> 500 users) I record an enourmous amount of disc writes (up to 18000
> blocks written each second) in the time where most of users are active.
> This IO activity causes wait-states on the disc interface (RAID5) and
> finally slows down my mailmachine. Is there a explanation for these disc
> writes respectively is there a possibility to minimize this activity.
> Stopping Dovecot on this machine causes stopping most of the disc activity.
> 
> Regards
> Rainer Sigl
> 
> 
Hi Rainer first you should upgrade to the latest stable of the 1.x branch
or better 1.1.x, also dapper is very old perhaps try hardy

then retest, i run 2000 users on suse with dovecot 1.0.15 and mysql
on sata 3ware hardware raid 1 500 GB on ext3 without any problems

-- 
Best Regards

MfG Robert Schetterer

Germany/Munich/Bavaria