Basically title. I’m in the process of setting up a proper backup for my configured containers on Unraid and I’m wondering how often I should run my backup script. Right now, I have a cron job set to run on Monday and Friday nights, is this too frequent? Whats your schedule and do you strictly backup your appdata (container configs), or is there other data you include in your backups?
btrbk works that way essentially. Takes read-only snapshots on a schedule, and uses btrfs send/receive to create backups.
There’s also snapraid-btrfs which uses snapshots to help minimise write hole issues with snapraid, by creating parity data from snapshots, rather than the raw filesystem.
I’m not familiar with that, but if it permits for faster identification of modified data since a given time than scanning a filesystem for modified files, which a filesystem could potentially do, that could also be a useful backup enabler, since now your scan-for-changes time doesn’t need to be linear in the number of files in the filesystem. If you don’t do that, your next best bet on Linux – and this way would be filesystem-agnostic – is gonna require something like having a daemon that runs and uses inotify to build some kind of on-disk index of modifications since the last backup, and a backup system that can understand that.
looks at btrfs-send(1) man page
Ah, yeah, it does do that. Well, the man page doesn’t say what time it runs in, but I assume that it’s better than linear in file count on the filesystem.