w3-total-cache fatal-error-500

W3 Total Cache HTTP ERROR 500, Call to undefined function W3TC\wp_unslash()

At the last update for W3 Total Cahe to Version 2.2.3 we reached the situation that the site no longer works, it returns a classic

IO linux Error

Fixing kernel error AMD-Vi IO_PAGE_FAULT – Linux

Without any clear reason, today an error appeared on my home server, in fact the server crashed and did not respond to any commands, the

WARNING-pool-server-reached max_children setting

Solved! WARNING: [pool ***] server reached max_children, consider raising it

If you encounter such an error in the php logs, then it is time to modify max_children. The php logs are usually located in /var/log/,  and