[Dovecot] Re: Dovecot memory use and settings

[Roger Weeks]

Okay, it appears to me that increasing auth_process_size above 256  
just doesn't make any difference to this problem.  It seems that  
someone else has reported this same issue with 1.0alpha5:

http://permalink.gmane.org/gmane.mail.imap.dovecot/9423

Does anyone else think this might be a mysql issue?  Or is this  
specifically a dovecot problem?

Even on really busy servers, I never see more than three auth-worker  
processes on either of our servers.  The dovecot.conf has this:
auth_worker_max_count = 150

But I don't see anywhere I can tell it a minimum number of auth  
worker processes to start when dovecot starts.  Is there an  
auth_worker_min_count or something similar?

--
Roger J. Weeks
Systems & Network Administrator
Mendocino Community Network

On Jan 12, 2006, at 3:43 PM, Roger Weeks wrote:

> We're continuing to have dovecot auth-worker failures once or more  
> times per day.  The symptoms are these in the log:
>
> pop1 dovecot: auth-worker(default): Out of memory (Needed 8164 bytes)
>
> or
>
> auth-worker(default): sql(lewis1,12.43.59.134): Password query  
> failed: MySQL client ran out of memory
>
> Timo suggested that we need to up the
> auth_process_size = 256
>
> However, we've tried increasing this to 512 and then 768.  The  
> comment on the entry says
> # Set max. process size in megabytes.
>
> These changes don't seem to make any difference.  On both of our  
> servers (RH ES4, 1MB RAM), we never seem to have more than 300MB of  
> RAM used.
>
> However, the auth-worker process continues to fail occasionally.   
> It does respawn itself after a couple of minutes, but in that time  
> all authentication for dovecot fails.
>
> Am I missing something else in the config?
>
> --
> Roger J. Weeks
> Systems & Network Administrator
> Mendocino Community Network
>
> On Jan 11, 2006, at 12:51 PM, Timo Sirainen wrote:
>
>> On Wed, 2006-01-11 at 12:40 -0800, Roger Weeks wrote:
>>> pop1 dovecot: auth-worker(default): Out of memory (Needed 8164  
>>> bytes)
>>>
>>> or
>>>
>>> auth-worker(default): sql(lewis1,12.43.59.134): Password query
>>> failed: MySQL client ran out of memory
>>
>> These are different from the system running out of memory. It's about
>> authentication process size hitting its configured limit. Default is:
>>
>> # Set max. process size in megabytes.
>> #auth_process_size = 256
>>
>> So it appears that it's trying to grow above 256MB at which point it
>> gets killed. This could mean that something is leaking memory, but I
>> don't remember other people having this problem, so it might be  
>> somehow
>> specific to your configuration.
>>
>> In any case those auth-workers are restarted automatically  
>> whenever they
>> die so it shouldn't be that big of a problem?
>>
>> There are also ways to debug this if you want to..
>>
>