[Dovecot] imap-login processes

[Bryan Polk]

On Sun, 25 May 2008, Timo Sirainen wrote:

> On Sun, 2008-05-25 at 05:08 +0300, Timo Sirainen wrote:
>> On Mon, 2008-05-19 at 12:06 -0400, Bryan Polk wrote:
>>> On Fri, 16 May 2008, Evaggelos Balaskas wrote:
>>>
>>>> -----BEGIN PGP SIGNED MESSAGE-----
>>>> Hash: SHA1
>>>>
>>>> I hope something like this could help you :
>>>>
>>>> # Authentication Cache
>>>> auth_cache_size = 10240
>>>> auth_cache_ttl = 18000
>>>>
>>>
>>> This may have done the trick! The number of imap-login processes has been
>>> holding around 60 all morning.
>>
>> So I guess most of the login processes were just waiting for
>> authentication processes to respond? I hadn't thought about that. How
>> many dovecot-auth processes do you have? Increasing
>> auth_worker_max_count might be a good idea.
>
> Or it should have actually logged an error in that case: "Couldn't
> create new auth worker".
>
> Maybe it's the passwd lookups that are slow? What NSS backend are you
> using? It's probably a good idea to make them use auth workers also:
>
> userdb passwd {
>  args = blocking=yes
> }
>

Right now (which is very low usage) there's only one dovecot-auth process 
and I remember looking at this at the time and not being worried about the 
number of auth processes, or I probably would have changed the default 
from 30.. Also, I never saw anything in the logs. I turned on 
"auth_verbose = yes" but not auth_debug.

We're using a rather old NIS server at the moment, planning to move to 
LDAP this summer.

Dovecot has been running smoothly this week since I turned on the 
auth_cache stuff, at times going up around 110 imap-login processes but 
never going higher. It's always responsive which makes the users happy. 
Thanks again for the great product!