[Dovecot] enourmous amount of disc writes

Richard Hobbs richard.hobbs at crl.toshiba.co.uk
Mon Jun 15 16:30:55 EEST 2009


Hello,

You might also want to enable "noatime" in the mount options for the
volume housing the data... if you're using maildir, this *could* reduce
the number of writes by half, theoretically!

Richard.


Robert Schetterer wrote:
> 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
> 

-- 
Richard Hobbs (IT Specialist)
Toshiba Research Europe Ltd. - Cambridge Research Laboratory
Email: richard.hobbs at crl.toshiba.co.uk
Web: http://www.toshiba-europe.com/research/
Tel: +44 1223 436999        Mobile: +44 7811 803377
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