Syncronize servers using rsync over SSH next door or across the world
Suppose that you have more than one server, and that you want to keep a backup of your unRaid server. Suppose that you have tried the sync options, but find that they are a bit finicky and unreliable. This is a totally reliable bullet proof / stable way to keep your backup server fresh. All you need is 2 unRaid servers connected to the internet, and we use secure keyed ssh to make the rsync commands secure and optimized for transiting the internet.
What I am using is a unRaid 6.2.
One more refinement was necessary.
Everything worked perfectly until I rebooted my main server. It is the server from which I am copying new files to the backup server. Generally, it is running 24x7 but, I upgraded it to 6.4.0 stable which required a few reboots to upgrade and to resolve a couple of minor issues. After reboot, the rsync operations failed. Although there was never a prompt for a password, my backup server was an unknown host.
After confirming the host