I just completed the migration of my synapse server from pi4b2 to pi4b1. This was because pi4b1 was running Plume, and had tons of spare resources. Now, pi4b2 is free to be something else!
I'm thinking of making it a backup server. I just realized I had a 640GB HDD lying around that I could plug in. That should be large enough to keep backups of Plume, Pixelfed, Mastodon, Postgres. and Gitea. I may have another, larger disc around here somewhere that I could use to also back up Nextcloud, but we'll see
I'm thinking about just setting up btrbk to do daily transfers of snapshots from my other devices with
btrfs send | btrfs recv
My first task is to figure out how to enable backups of btrfs subvolumes without requiring SSH-ing in as root.