[Dovecot] Very High Load on Dovecot 2 and Errors in mail.err.

[Urban Loesch]

Hi Javier,

thanks for your help.

Am 20.05.2012 13:58, schrieb Javier Miguel Rodríguez:
>
>
> I know that you are NOT running RHEL / CentOS, but this problem with
>> 1000 child processes bit us hard, read this red hat kernel bugzilla
> (Timo has comments inside):
>
>
> https://bugzilla.redhat.com/show_bug.cgi?id=681578
>
> Maybe you are
> hitting the same limit?


yes maybe.
The only strange thing is that I don't see any erros in my dovecot logs.
I don't see erros like "Panic: epoll_ctl" ore something else.

I checked my kernel and the patch mentioned in
https://bugzilla.redhat.com/show_bug.cgi?id=681578

(comment 31) is not applied. It comes in version 3.0.30 and 3.2.17.

I will see what tomorrow happens under more load.
If I have the problem again, I give 3.2.17 a chance.

thanks
Urban

>
> Regards
>
> Javier
>
> El 20/05/2012 11:59, Urban
> Loesch escribió:
>
>> Am 19.05.2012 21:05, schrieb Timo Sirainen:
>>
>>>
> On Wed, 2012-05-16 at 08:59 +0200, Urban Loesch wrote:
>>>
>>>> The
> Server was running about 1 year without any problems. 15Min Load was
> between 0,5 and max 8. No high IOWAIT. CPU Idletime about 98%.
>>> ..
>>>
>
>>>> # iostat -k Linux 3.0.28-vs2.3.2.3-rol-em64t (mailstore4)
> 16.05.2012 _x86_64_ (24 CPU)
>>> Did you change the kernel just before it
> broke? I'd try another version.
>>
>> The first time it brokes with
> kernel 2.6.38.8-vs2.3.0.37-rc17.
>> Then I tried it with 3.0.28 and it
> brokes again.
>> On friday evening I disabled the cgroup feature
> compleetly and until now
>> it seems to work normally.
>> But this could
> be because we have weekend and now there are not many
>> connections
> active. So I have
>> to wait until monday. If it happens again I will try
> version 3.2.17.
>>
>> On the other side it could be that the server is
> overloaded, because
>> this problem happens only when there are
>> more
> than 1000 tasks active. Sounds strange for me, because it has been
>>
> working without problems since 1 year
>> and we made no changes. Also
> there were almost more than 1000 tasks
>> active over the last year and
> we had no problems.
>>
>> thanks
>> Urban
>
>