[Dovecot] POP3 error

Thierry de Montaudry thierry at mailhub.co.za
Thu Mar 10 10:14:49 EET 2011

On 09 Mar 2011, at 20:16, Timo Sirainen wrote:

> On 8.3.2011, at 19.42, Thierry de Montaudry wrote:
>>> So... if the httpd process is the one consuming all of the CPU, doesn't
>>> it stand to reason that it might be something to do with one of your web
>>> apps, and not dovecot?
>> But then why was it fine with 1.1.13, which never had once this problem in 2 years? or is 2.0.9 slower, or consuming more resources to create the problem?
> One possibility is that maybe v2.0 works a bit differently.. Maybe it causes webmail to use a new feature that wasn't yet in v1.1, which causes more CPU?
Yes, possibly. I will investigate the features that the webmail might use now that it was not previously.
> I also just heard that apparently this "Resource temporarily unavailable" can happen if service imap/pop3-login's client_limit is too large. I'm not really sure why, but you could try reducing them to e.g. 50.
I reduced the limits with process_limit. I'm wondering if I should use the client_limit as well, but couldn't find much documentation, would you have any light on that?
> Do you remember how high the CPU usage was at peak times in v1.1? Has that changed? Is the problem maybe that v2.0 just fails in a different way by logging these failures, where v1.1 wouldn't even accept as many incoming connections?
v1.1 was about the same as current, load avg between 3 and 4 from 9pm to 4am, no change on that side. It looks like it's just when there is spikes, the new version is reaching some limit.

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