This was being caused due to a known issue with nss-softkn. See this article: https://www.splyt.com/blog/2014-05-16-optimizing-aws-nss-softoken
When I run free -m from my centos 6.5 box I am seeing that I only have around 1400 mb of available ram, including the cache. When I do top, sort by memory and add up the processes I am only seeing around 1600 being used. I should have a LOT more free memory. This is happening on a couple of our boxes.
[root@db1 ~]# free -m total used free shared buffers cached Mem: 7840 7793 47 0 287 1357 -/+ buffers/cache: 6148 1692 Swap: 7983 7 7976
Here is a better way to visualize the memory consumed by the processes: