[ADMIN NOTE: Profanity removed per TOU] This is so much more complex than it should be. I have just gone through this fiasco myself and would have had a coronary with this process should I have not had solid backups in place. Someone really needs to get their kicked for designing such a poor excuse for RAID volume management. This is completely worthless! There is my rant. If you own an S100, we have MANY, you had better be prepared to monkey around with sensitive drives and connect them to other machines if you want to rebuild an array. This should have never made it into a PowerEdge Server. NEVER.
Also, Make sure that you delete the 'NonRAID' Array (Virtual Disk 2 in my case) and not the RAID Array(Containing your OS and data)
Thanks for posting this. I ran into this last night after upgrading a T310 to Server 2012 R2 Essentials. I was not able to assign a hot spare and rebuild the array using the bios ctrl r and diskpart clean. I had to install Dell OpenManage Server Administrator Managed Node(windows - 64 bit) and after hooking drive externally to another computer and running diskpart list disk, select disk 2(in my case***), clean, I was also able to assign hot spare by clicking the name of the virtual drive "none" in my case and then selecting the disk action hot spare. Also, openmanage after installing it opens a web page with a login up top, I had to click cancel on that one and then on the black login screen I used my server creds to login.
KOMBAT_WOMBAT - Thanks for persevering with all the details, had exactly the same scenario and your write-up has brought me to the same solution and conclusion!
Our PowerEdge R210 using PERC S100 RAID 1 is now rebuilding the virtual disk!
Must agree with the headaches had during the process - not as intuitive as one would expect. The RAID utility at boot (CTRL+r) didn't help after doing DiskPart.exe (on the replacement drive) - as after removing the Non-Raid volume it automatically put my (replacement) disk into Online state and the hot-spare option became greyed-out thereafter. I then had to boot into the OS and use the Dell OpenManage Server Administrator (OMSA) tool as you described.
Nevertheless, 2 full days (of fiddling) later and its finally rebuilding!
Companion, I am trying to perform the process you suggest but it throws me an error when
removing the virtual disk (Error: To exit multi-selection menu without selections, you must use),
please help, I need to recover the file server.