Mysql and FTP server stops or crashes
We have a small server running on Ubuntu 14.04 with the Wordpress one click install. I've added a ftp server so we can upload certain files. The FTP server stops working every x-days/hours/minutes, but after a "service proftpd restart" command it works again.
When our site went live yesterday, the Mysql server stopped working as well (this happened twice), and after a reboot start working again. It had a peak of 100 simultaneous visitors.
Any idea what the problem might be?
P.s. server details: 512MB Ram 20GB SSD Disk Amsterdam 2