Hi I found it… During boot of server, Press to run RAID Controller BIOS Utility.  Would have been nice to be able to fix in iDRAC while server is running. On the other hand, my test would properly not happen in production. Thanks
I have a R630 with PERC H730 Mini (Embedded) and 8 physical disks. Configured 7 disks in RAID5, and 1 disk as Hotspare. During a failover test, the Hotspare and one disk in the RAID was removed The disks was plased back in the server and the RAID rebuild completed without errors, all OK. But I cannot see the Hotspare. Error in iDRAC8, Storage -> Controllers -> Setup -> Foreign Configuration: STOR018: No foreign drives detected.  If the only foreign drives present are in a secured state, run a secure erase operation on the drives and retry the operation. Otherwise the operation was not successful because there are no foreign drives. I can see the Disk in iDRAC8, Storage -> Physical Disks -> Properties -> Health and Properties, listed as “Foreign” How do I  “run a secure erase operation”? And will the secure erase operation only erase the Foreign disk? Thanks 
STOR018: No foreign drives detected