Rory

Thanks, that was pretty easy/quick and and it seems to be rebuilding etc fine now.

I have 4 drives, all 4TB. One of the disks I guess had/has problems and was sitting "unassigned". I shut down, pulled it out, popped in a new one, then stopped the array, set it as a 4th data disk by mistake, started array and saw 16tb available, realised my mistake, stopped array. Now the only valid configuration is to boot up with a 0 parity 4 disk array. What's the best way to proceed? I'm guessing I have to boot this array and follow a procedure for "downscaling" an array, then remove the 4th disk and hopefully get it back to unassigned?