I've got a 4 drive RAID5 array. One of the drives quit working quite some time ago. Another drive (/dev/sdc)just started developing read errors so that now the array will not mount.

I've got a new drive (same model# as the ones in the RAID5 - 250 gb) and want to copy the data from /dev/sdc to the new drive. I've got ddrescue ready to execute. Running Ubuntu Server 8.10 with the OS on /dev/sdd - a dedicated 80 gb hdd.

  • Can I disconnect the other drives in the RAID5 so that the only one connected is /dev/sdc (the source for the copy)?
  • Can I simply connect the new drive to one of the newly emptied slots and run ddrescue?
  • Or, do I have to issue some kind of commands to do a low-level format and designate the drive something unused (such as /dev/sdf)?
  • What is the process for installing the virgin hdd and copying the data to it?