Synchronization of the web server with the backup. Where to dig?

Question

linux

There is a combat web server - VDS. It has several projects (PHP+MySQL). Task: to raise a backup server, which would be "equal" to the main one (sorry, I'm not an admin). Tell me where to dig. I want to hire a pro, but how to set the task correctly and what words to hear from him in order to understand the degree of his competence?

Answer 1

mysql - phpmyadmin - can make a master slave server.!
csync 2 - files
GlusterFS - sync at the file system level.
Ansible - synchronization of all configs of dns server settings, etc.
well, rsink.

Answer 2

For what purposes is the task to raise a standby server? If this is not the best solution for data backup