For the backup server currently I have a computer with an AMD Ryzen 3 2200g with 8gb ram, a 256gb nvme and 4 18tb hard drives – I believe Seagate Exos… It’s a very weak computer but it is really only a backup computer. For redundancy I configured the drives in a software raid where they are paired and mirrored, meaning, in theory, I could at most lose 2 disks as long as they are from different pairs.
I wanted something that could be fast for backups but it seems that connecting 2 computers is very slow unless you want to go very expensive and get all fiber stuff.
So I stuck to better than 1gbps but not by much, 2.5gbps, I bought the cheapest switch that had 4 2.5gbps RJ45 ports and 2 10gbps SPF ports, I also bought a pcie 2.5gb card, very inexpensive. And also a USB 2.5gb adapter, because the main server has no pice ports that it can spare.
I used duplicacy to do the backups, you can set repositories for backups in ssh configurations so I basically just have the repositories set via ssh, the program automatically then creates a sfpt server on the backup machine and starts copying the new contents of the backup. Only what is changed is transferred.
To automate all this in my daily life I simply configured WoL on the backup server and added the shutdown command as not needing sudo on the backup machine. So now every day at 4 am, the main server wakes the backup server up via magic packets, starts the backups of everything and afterwards sends the shutdown signal.
It’s nice to mention also that the backup server is usually shutdown and that it is also connected only to the main server and not to any other machine. This means that the data backup is, in a sense, “air-gapped” increasing security of the backup. And the fact that the system is off also improves it’s longevity by not reducing power on hours.
In the future it would be great to improve multiple things. It would be better for the system to have NAS software, for example, TrueNAS, especially because it would improve the reliability of the system and the monitoring of the physical hardware, especially, of course, the hard drives.
It would also be nice to improve the connectivity, getting space to connect a 10gb pcie card would be really nice to improve the backup speeds.