If you replace a disk in an IBM Storage, such as a DS4700 and the disk is not rebuilding and is instead a new disk. You can set the disk as a replacement disk with the following command:
replace drive [85,12] replacementDrive=85,12;
To put the hot spare which was in use back to a hot spare, use the following command:
set drive [0,1] hotSpare=TRUE
This can be done in the Main storage manager view. Highlight the system, right mouse click and choose “Execute Script …”. Put in the commands and select “Tools” –> “Verify and Execute”.
Your initial lun will rebuild and your hot spare will fall back to the hot spare.