FreeBSD 10 & default_vsz_limit causing reboots?

[Timo Sirainen]

On 24 Sep 2015, at 22:36, Rick Romero <rick at havokmon.com> wrote:
> 
> Quoting Timo Sirainen <tss at iki.fi <mailto:tss at iki.fi>>:
> 
>> On 24 Sep 2015, at 16:26, Rick Romero <rick at havokmon.com <mailto:rick at havokmon.com>> wrote:
>> 
>>> Update.  Only a single reboot has occurred since changing
>>> defalt_vsz_limit from 384M to 512M.  It would seem that something the
>>> users are doing is causing that virtual memory size to be exceeded
>>> (possibly a mailbox search?), and when that occurs Dovecot/FreeBSD is not
>>> handling the event as smoothly as expected.
>>> 
>> I could maybe understand that a system might reboot in some conditions when it runs out of memory, but you're doing the exact opposite of avoiding that by increasing the vsz limit. It just means that the system is potentially going to use even more memory. And wouldn't FreeBSD have something similar to Linux's out-of-memory killer?
>> I think either your hardware is broken or FreeBSD has some serious bug, and a hardware problem seems more likely to me.
> 
> I was thinking along the lines of the process kill handling (? I don't know what actually occurs when the limit is reached - I'm assuming a thread is terminated) was triggering something odd in FreeBSD.
> 

Yeah. That would fit into the "serious FreeBSD bug" category. If a limit is reached, kernel is supposed to send SIGKILL to the process.