Little research how rm -rf and tar kill server

[Mark Felder]

On Sat, Mar 28, 2015, at 15:22, Artem Kuchin wrote:
> 
> So, questions and thoughts:
> 1) Why i had no problem such this in fbsd 9? I think the reason for the 
> problem is in kernel, not in hardware or mariadb+nginx because server 
> load did not
> increase at all, even decreases a little.

This is only anecdotal until you run the exact same OS version and load
on the old hardware which had a different motherboard and (probably)
disk controller. Can you provide us with any further hardware details
between the two systems?

> 2)  I consider it a sever bug, because even normal used (and i have 
> plenty of them using ssh) can eventually do rm -rf and kill all sites. 
> Which means there are
> must be some way to limit io usage per user
> 

ZFS has far superior disk IO scheduling. You may have more success with
that. Unfortunately I'm not aware of a way to limit user/process disk IO
on FreeBSD.