Longer lasting I think; leave it powered on and warm.

Best in reality; buy 3 drives, and after you do a backup move one off site.

3-2-1-1

I don't think unmounting in itself does any difference to it's longeviy. I think what you want is powering it down.

Mounting or unmounting a filesystem won't make a difference for drive longevity.

If you want to keep your backups secure, you want to keep them offline, so if you get ransomware it doesn't encrypt your backup too. (Or if you just mistype a command and target the wrong device, folder, etc.)

But drive motor starts and stops are when the most failures occur. So the ultimate question isn't how to make a drive last longer, it's how you plan to handle it when the failure inevitably occurs.

I recently bought a second external drive to do a backup of the first one. In the process I'm going to switch to btrfs. It can do data scrubbing which allows for self repair of corrupted data, which can occur if you leave a drive unpowered in a closet for some years.

@alvaro @selfhosted @selfhost

How many hours do the specs say it last?

Hmm. I unmount mine to reduce noise. Didn't think about endurance though, curious to see opinions too.