= OOM - Out of Memory =

Am oom refers to both RAM and SWAP all been used up. It pretty much cripples the server. By default an oom_killer kicks in and should kill the offending process. However with a lamp stack (MySQL and Apache) oom_killer does not do a good job (in my opinion).

99% of the time, I had to do a hard reboot on the server as the console was not responding.

If an OOM does not happen often, you can simply tell the server to reboot on oom.

vi /etc/sysctl.conf #Add the following vm.panic_on_oom=1 kernel.panic=10 #60 = wait 60 seconds before rebooting.

echo 1 > /proc/sys/vm/panic_on_oom echo 60 > /proc/sys/kernel/panic

http://www.linode.com/wiki/index.php/Rebooting_on_OOM

https://syslog.tv/2011/10/25/rebooting-on-oom/

https://access.redhat.com/site/documentation/en-US/Red_Hat_Enterprise_MRG/1.3/html/Realtime_Tuning_Guide/sect-Realtime_Tuning_Guide-General_System_Tuning-Swapping_and_Out_Of_Memory_Tips.html