I had a Seagate external drive fail on me today, taking with it whatever I had on there that wasn't in Git Annex (mostly a bunch of old backups, but also my very latest backup which I hadn't got around to hashing yet). I shucked the drive and put it in a real computer, but although the motherboard can see it, Windows doesn't seem to think it exists. So I suspect the drive's controller might have died.

It seems a bit silly to have to think about backing up my backups, and a backup/archive drive which can be expected to fail after a couple of years isn't that useful, so I'm looking to replace the drive with something more reliable, so this doesn't happen again.

Is there maybe something I can plug into my USB port that will do RAID mirroring across a couple of disks, and which has a long warranty (5 years? 10 years?)? Bonus points if it's cheap, because my replacement budget for shit breaking isn't too high. Double bonus points if there's a mathematical model I can use to figure out the expected number of years my data will survive if I entrust it to such a system (and change out dead disks).

If I shell out for a solid state external instead of a spinning disk, how long can I expect it to last (under a not particularly taxing write workload) until its circuitry fails?