The most common reason why MySQL is not running is that it stopped or failed to start as a result of not enough memory.
This can usually be seen by attempting to start the mysql server (“service mysql start” on Ubuntu and some other systems) and then reviewing the mysql error log (usually in /var/log/mysql/error.log or similar file path).
A useful program to review the logs one page at a time is “less” –for example:
If you see memory issues such as “mmap can’t allocate” then you can be sure that you are having memory issues.
Potential solutions are:
1) upsize to a larger server. We recommend at least a 1GB droplet for any server utilizing a MySQL database.
2) Enable swap space, which functions in the same way as RAM, except it’s slower since it’s using disk space to simulate RAM. Your system uses this only in the case where you run out of RAM, and it’ll likely result in slower responses from your site, but if you add enough swap (generally twice as much as the amount of RAM you have is a safe bet) it should prevent MySQL from crashing and causing your site to go down. You can find a guide relevant to your Linux distribution here: