Thanks guys!
Yes, just a bad SMART status.
Will this work:
1/ Move the content of the "faulty" drive over to the remaining drives.
2/ Take the array offline, shutdown and remove the drive.
3/ Boot up, run the "New config" (scary, have never done this before ), will this only see the drives that are left in the array and give them new numbers?
4/ Take the array online and run a parity check.
In "New config" it says: "This is a utility to reset the array disk configuration so that all disks appear as "New" disks, as if it were a fresh new server."
Does this mean that all data on the rest of the drives gets wiped?
Cheers
/E