You MUST address the foreign configuration before you can do ANYTHING with that disk.  In this case, you need to CLEAR the foreign config. You can do this in OMSA, Storage, PERC, Information/Configuration, Foreign/Clear from the dropdown menu of Available Tasks for the controller.  Then you can assign it as a hot-spare.
Hi, I have a couple of Dell PowerEdge R320 servers that I needed to perform maintenance on. Each server has 3 disks in a RAID 1 config with a dedicated hot spare (disks 0:1:0, 0:1:1 and 0:1:2). I needed to make some emergency changes and needed a roll back. I did the following 1. Power off server2. Remove disk 0:1:13. Powered on server 4. Configured application x,y,zBecause it wasn't clear whether my config changes would work straight away, I simply popped disk 0:1:1 back in and left the server with 2 disks and an unassigned hot spare. Several weeks have passed and I now need to assign disk 0:1:1 as a hot spare. Within Dell OMSA and DRAC I do not have options to assign foreign disk "0:1:1" as a hot spare. On a server reboot I get the message "Foreign configurations found on adapter. Press any key to continue or 'C' to load the configuration utility, or 'F' to import Foreign Configurations and continue). I usually just ignore these messages and after a minute or os, the server loads into Windows. Could someone please point out the exact steps I need to undertake to be able to assign disk 0:1:1 as a hot spare. I suspect it's relatively straight forward, but I need to avoid a mistake like the plague as accidentally blatting this particular server would be very bad for my health! Thanks
How to clear a foreign disk config on a Power Edge R320