[CentOS] OOM and Swappiness

Wed Sep 16 17:33:27 UTC 2015
Gordon Messmer <gordon.messmer at gmail.com>

On 09/16/2015 09:11 AM, Callum Scott wrote:
> It is running a little
> tight on memory and so there have been a couple of events where the
> OOM_killer has been invoked and killed off MySQL, which you would expect.

One thing that should be noted is that regardless of swappiness, 
overcommit might be an issue.  If a single process is using most of the 
memory in a system, and attempts to fork(), as it will if it calls 
system(), then the system may require that there is enough memory for a 
second instance of that huge process.

This is one of the reasons why swap should be as large or larger than 
system RAM.

If you have very little swap, you should consider allocating more, or 
reviewing the overcommit options in addition to the swappiness settings.