[Dovecot] Re: Dovecot memory use and settings

[Tomi Hakala]

Roger Weeks wrote:
> 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?

I think it is a Dovecot problem if your system is 64bit.. I have
seen something similar.

> 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?

There is no such option, more workers are spawned automatically if
all current workers are busy.

Tomi Hakala

> -- 
> 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..
>>>
>>
>