Searching for this gave me lots of results that didn't answer my question, so here goes: I have a 2x2TB RAID-1 in my Mac Pro, and one of the drives is making a strange click sound. I'm not sure if it is seeking or what, but I was wondering if I could pull out one the 2 drives that makes up the RAID and boot the Mac Pro. If there is a drive failure, can I just put the one that still works into an external enclosure and copy it onto a new RAID ? They're Hitachi 2To Deskstar 64Mo S-ATA III 7K3000 drives which are very quiet, so I don't know if this noise is inherent to RAID-1 seeking or signs of a looming hard drive failure. Thanks for the help.