backup - Can I clone a root file system of a running server via ssh?

I want to make a backup of a running server. Every config files and everything without turning it off.

How can I accomplish this? Is it ok to try copying it all? Because I had problems with the root directory.

I don't want to make a lot of experimentation also because it has an important configurations.

I'm trying to make all this via ssh. How can I do this backup?

Any Ideas?