Thanks for the tips. Surprised there's not an open-source/free option for this out there because I think the Btrfs RAID is for same sized drives (but I could be wrong).

Pooling isn't essential but I guess it is a requirement for some sort of RAID style redundancy so I'm happy to pool, but I'll probably need another drive to help with data transfer then add it to the array.
 

Have you considered something like Crashplan for backing up. RAID offers some redundancy, but it's not magic. And remember, when you swap a broken drive, it's going to stress the others. I've seen loads of RAID 5 rebuilds take another drive out, leaving no choice but a restore from backup.

That looks interesting too. Lately I've had no interest in backing up everything, with only doing select folders with Karen's Replicator nightly to maximise my storage with a bit of security but drive failures have annoyed me enough and I like the idea of pulling a dead drive from an array and sticking a new one in without having to try and do loads of data recovery. I definitely see your point on stress to drives on a rebuild.

I've not even pulled my most recent dead drive yet.

My other problem is that I need to massively sort out my storage in general because I'm not even sure what I've lost on that drive.

Well the drive was a 500 GB drive and I have 326 GB of data from it backed up, turns out there was a lot of photos on it, phew!

I've just started using Crashplan on the 30 day trial. Looks ideal really now I've got a reasonably decent upload speed. Price isn't bad either, especially since I'll only be using it on one computer (my server) so I can go for the cheaper package.

Ooh, interesting! Do keep us updated, I looked at it before and I just wasn't totally convinced it would be as painless as it should be.

Well the initial upload process is definitely going to be the hardest (or longest) bit.

I've currently /only/ selected about 500GB of data, going to take days.

A little bit disappointed with the upload speed.

Seems to go under 2MBit/s which is a bit rubbish considering my upload bandwidth is over 10Mbit.

11 days to go !!

The 30 day trial has now expired.

I guess it's quite difficult to really test how good or bad the service is without a disaster. Currently got about 500 GB backed up.

I guess it's worth a punt for 12 months and I think I've got a 20% off code somewhere.

You can pay monthly and just cancel if you change your mind. I've not had to restore much off it, but I've grabbed a few files back and it's always been fine for me.

I just went for the full 12 months. Just leave it in the background and assume it's all there.