Right now I’m creating a nightly restic snapshot of my server on borgbase and on some spare drives, and keeping the snapshots forever. There’s a ton of daily churn in my data though, between databases and logs and other files that don’t constitute ‘real data’ but might be needed to restore the app.
Zero or one backups depending on the type of data generally.
For a system if it can’t be redeployed from a list of requirements then I Foundationally ducked up. It means either I’m depending on something fragile, unknowable or over complicated.
Raw data on the other hand goes on a raid array. If I need more redundancy then that, then a single extra off site backup on a cd or something.
A back up on the same drive as the original isn’t a backup. It’s a waste of space, and a stupid idea.
A system that requires excessive nonsense is not reliable.
If I have a on and off site back up and both fail. Then either the world is literally fucking on fire and it doesn’t matter. Or someone dropped a bomb on my storage.
Either way I have bigger problems at that point.
It’s a backup that helps against software errors, but not against drive failures. Depending on what you want to achieve, it’s a perfectly valid strategy.
I generally have Operating System backups that are stored on the same drive. Those backups are immediately copied to 3 different devices, my computer and two other drives
The backup on the local drive is useful for when I’m tinkering, making adjustments, adding or removing stuff. Restoring from that local backup is far more convenient than using the remote backups
I don’t use anything with a database so all my static media files and wiki’s don’t go to the local backup. I handle them separately but they are still spread across the 3 other devices in my network