This is a genuine request from a friend of mine who has a website and needs to be backed up in a hot stand-by server in case the production goes down. The command that I am using is ‘rsync’.
Firstly, you’ll have to install rsync on both boxes if you have not done so:
sudo yum install rsync
usually will do the trick
Secondly, I use the following command on the stand-by server to 'back up' all the PROD website's files:
sudo rsync -rtavue ssh email@example.com:/home/wwwroot/default/ /home/wwwroot/default/ --delete
The above command will ask your local password first and then your password on the PROD server.
--delete gets rid of all files that no longer exist on the PROD side.
BTW, here is a better tutorial all about ‘rsync’.