What is mysql configuration error?

Question

MySQL

VDS specs:
CPU2 x 2.7GHz,RAM512Mb,xvda15Gb,LAN10Mbps
Server settings come by default with vestacp.
Screenshots of htop and my.cnf

In the previous installation and server settings on the same hardware with the same vestaCp panel, sites flew.
Now, after restarting apache and mysql, for some time (about 30 minutes), the sites work at medium speed. Later they start to slow down and almost do not load. The panel shows about 2 GB of memory for Apache and about 4.5 GB for mysql. After a restart everything works fine again. Why is this happening? How to deal with it. Attendance in total from all sites 10 people per hour :)

Answer 1

But I didn’t try to switch to centos or debian, since it works for me on debian and the same problem on ubunte

Answer 2

Hardly a problem with muscle or apache configuration. Rather, you were hacked again and you unwittingly participate in DDoS or botnet :)