[Dovecot] imap-login processes

[Timo Sirainen]

On May 16, 2008, at 6:56 PM, Bryan Polk wrote:

> On Fri, 16 May 2008, Timo Sirainen wrote:
>
>> How many imap processes do you have at that time? Each SSL connection
>> uses up one imap-login process.
>>
>> One sure way to fix this would be to change to high-performance  
>> mode as
>> described by http://wiki.dovecot.org/LoginProcess
>>
>
> Currently 74 imap processes, 336 imap-login processes.

It would help to know what these extra processes are doing.  
Unfortunately there's no simple way to do that.. Maybe writing a  
script that trusses the processes for a few seconds and then seeing  
what it shows?

Another way would be to try if LINUX_PROCTITLE_HACK works also with  
Solaris. You can remove the comments around #define from src/lib/ 
process-title.c and then set verbose_proctitle=yes. This should first  
be tested though, because if it doesn't work it could break badly. If  
it does work, you should at least see IP addresses for each process  
that has a connected client and also TLS if SSL/TLS is being used. It  
could probably also include username for SSL proxies.

> I tried switching to high-performance mode yesterday.. It seemed to  
> end up with sort of the same results, though harder to diagnose.  
> Each process I guess ended up hitting the login_process_size = 64  
> max and then stopped responding.

If it hits that limit, it gets killed by signal 9 by the kernel (and  
that gets logged). It's also a good idea to then increase it to  
something like 256. But I can't see why it would stop responding then.

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