[Dovecot] auth service: out of memory

[Timo Sirainen]

On 29.6.2012, at 10.39, Mailing List SVR wrote:

> Il 29/06/2012 09:19, Timo Sirainen ha scritto:
>> On 29.6.2012, at 9.35, Mailing List SVR wrote:
>> 
>>> I have some out of memory errors in my logs (file errors.txt attached)
>> How large is your auth process's VSZ when it starts up and has handled a couple of logins? It's possible that it's not leaking at all, you're just not giving enough memory for its normal operation. Some Linux distros nowadays build binaries that eat up a lot of VSZ immediately when they start up.
>> 
>> 
> ps aux report this:
> 
> dovecot   7454  0.0  0.0  85980  3776 ?        S    09:36   0:00 dovecot/auth
> 
> before restarting dovecot the auth process was running since about 1 hour and this is the output from ps aux
> 
> dovecot  25002  0.0  0.0  86112  3780 ?        S    08:24   0:00 dovecot/auth

So you have 44 MB of VSZ available after startup. You also have 10 MB of auth cache, which could in reality take somewhat more than 10 MB. It doesn't leave a whole lot available for regular use. I'd increase the auth process's VSZ limit and see if it still crashes.

If you want to, you could also test with valgrind if there's a leak:

service auth {
  executable = /usr/bin/valgrind --leak-check=full -q /usr/libexec/dovecot/auth
}

You'd then need to restart the auth process to make valgrind output the leaks.