Originally Posted by
peterb
2. RAID 1 is NOT a substitute for backing up. True it mitigates against a single disk failure, but it doesn't protect against a failure of the controller, or of the entire system, or (for example) corrupted data being written to the disk system - it will corrupt both disk file systems.
However...
You could, create (using repartitioning software, and if your disk has space, create two empty partitions and RAID those, then store data on that, but it would be a bit of a faff and messing with partition tables always carries some risk.
Otherwise, if you really want to go the RAID route, create the array from two new disks, and then clone your existing disk to the newly created array. You could then keep the old drive (in say a USB caddy) as backup store
But...
RAID 1 is really suitable for servers where resilience and uptime is important (assuming you have a RAID system that supports hot swapping). Raid 1 is useful for many things, but a substitute for a proper backup strategy isn't one of them!