Why is the server hanging?

Question

Debian

Hetzner rented a server, it costs ESXi 5.5 with several virtual machines. One of my virtual machines with a web server on debian and four simple sites has been periodically freezing lately. Installed atop and saw before hanging g approximately the following picture.

Processes that load cpu change, most of all mysql, nginx, php-fpm and others. I'm trying to understand the root cause of a large disk ping. This crumbled disk causes latency and, accordingly, cpu loading by squeaking / reading processes, or vice versa, processes load the disk. In general, where to dig, what to watch?
After rebooting the virtual machine, everything works fine for the time being. Maybe it hangs in a week, maybe twice a day ..

Answer 1

View disk smarts
Logs before freezing
Change disks