Hi Kawin, Great info, clears things up on my side. Here's it. Delete the Non-RAID VD, in this case of the last screenshot, the bottom VD. After deleting, a hard disk will be available for the hotspare assignment. Rebuild should kick in, soonest a hotspare is available. Let me know how it goes. : )  
I have PowerEdge T110 II   with RAID 1 created.     The disk0  has  failed.  At the moment only disk1 is running.   I would like to replace disk0 with a new harddrive and make it mirrored (raid1) with the disk0.   How do i rebuild Raid1 ??? I've been searching for option "Rebuild"  but did not find any look like it.  Regards,  Kawin
How to rebuild Raid1 on Poweredge T110 II