It’s very important!!!

Swap will auto release (or free) the unused memory.

We setup an jenkins ci server, run functional test on firefox use xvfb. After some hours, the memory is almost full.

So we add swap to our ci server.

Example: https://www.digitalocean.com/community/tutorials/how-to-add-swap-on-ubuntu-14-04

Reference:

http://stackoverflow.com/questions/29764181/jenkins-email-ext-plugin-pre-send-scripts