[BlueOnyx:12602] Re: Dovecot dies with anvil too many open files

[Gerald Waugh]

On 03/22/2013 08:38 AM, David Thacker wrote:
> Greetings all,
>
> I have a recurring problem where Dovecot chokes under heavy load (login
> break-in attempts) and has to be manually restarted. The problem used to
> happen once or twice a month, but lately happens at least once a day and
> is now a reliability problem for my hosting clients.
>
> I do have the Security > Login Manager > Host rule set to 30/h but it
> doesn't solve it.
>
> I will get an Active Monitor texted to my phone within 15 minutes of
> Dovecot choking, but if it happens overnight it can be several hours
> before I notice and can correct it.
>
> The problem reported in the mail logs is this:
>
>      Error: net_connect_unix(anvil) failed: Too many open files
>
> which is exactly as this poster described on the Dovecot mailing list
> here:
>
>      http://dovecot.org/list/dovecot/2012-October/069070.html
>
> A response to that post offered this suggested solution:
>
>      http://dovecot.org/list/dovecot/2012-October/069111.html
>
> which was to increase the max open files allowed for the Dovecot process.
>
> On my system when I "cat /proc/<pid of anvil process>/limits" I get:
>
>      Max open files            4096                 4096
> files
>
> So, I stopped & killalled Dovecot, then did "ulimit -n 8192" and then
> "service dovecot restart", and when I check again, I still see max open
> files 4096 instead of 8192.
>
>
> 1. Can anyone help me figure out how to increase the max open files that
> Dovecot anvil has to work with, to see if this will solve the heavy-usage
> choking problem?
>
> or
>
> 2. Can anyone suggest a way that the Active Monitor script that recognizes
> that "The POP server is not running and could not be restarted" could be
> modified to actually restart Dovecot on its own so I don't have to do it
> manually?
>
we use iptables rate rules to stop these (published earlier)
have thousands of blocks by iptables, makes a big iptables log file, but 
dovecot keeps running

-- 
Gerald