[BlueOnyx:12600] Re: Dovecot dies with anvil too many open files

[Jeff Folk]

On Mar 22, 2013, at 8:38 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 get these, too, although not with as much regularity. I put dfix in place from Solarspeed's free bundle:

http://www.solarspeed.net/blueonyx/free-products/free-bundle.html

It does a remarkable job at stopping these.

> 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?
> 
> 
> Regards,
> 
> dAvid tHacker                                  Email: David at ThackerNet.com
> Thacker Network Technologies Inc.                http://www.ThackerNet.com
> 
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