I don't think your metadata comment is true in the case of RAID-1. Mirrored RAID shouldn't need much of anything for metadata. I've only ever used both cheap RAID cards and motherboard RAID, doing a standard mirrored RAID-1. I've had multiple drive failures, and I've never had a RAID where I couldn't unplug one of the drives from the array and just use it independently of RAID without any issues. Its pretty easy to test, but I know I've taken drives out of a mirrored array and used it as an individual drive without problems.