If your concern is space, use RAID5 or RAID6, which offer single or dual disk recovery. There's been some concern raised, particularly about errors on RAID5 rec

If your concern is space, use RAID5 or RAID6, which offer single or dual disk recovery. There's been some concern raised, particularly about errors on RAID5 recovery - the large disk sizes may make a failure during recovery more likely, but in my experience drives more often than not fail completely and totally, all at once or close to it. If you're extra worried about recovery though, my friend has a good setup where he keeps 1 TB RAID1 across all of his 4x8TB drives for personal files and uses the rest in RAID5 for media storage.