SAS 5i/R definitely supports 'hot spare.' BUT, the whole RAID ability in the controller is very non-intuitive. I should be able to take a BRAND NEW, exact same model drive, and just plug it in - where I removed, let's say, a 'bad drive' - and it all should work, but it does not seem to see/use the new drive, depending on how it is formatted and so forth.
And it seems you can up to 4 RAID configs on one SAS 5i/R card? You can scroll through them, with Alt-N. This is SAS 5i/R in a Dell PE 860, and no, there is NOT any option to 'add a drive,' not in my config, not with latest firmware and drivers and so forth - if there was, that would be perfect! Adding a hot spare did work at one point, but now it just sees "failed raid drive" and won't let me add it.
I was even able to synchronize, briefly. I did a whole 'synch,' thinking I could take the secondary drive (Drive 1 in my case) and plug it into a 2nd Dell 860 and all would be perfect (like 'imaging' - build several copies and use them in my multiple other servers - which I am licensed for), BUT, it lets the other server BOOT from the "synched" drive, but not re-establish the array.
Even on the SAS Controller page, it shows "Create IM volume - you can copy the data from Volume 0 to 1" (not those exact words, but you get the idea), but that is NOT true! On a "Create RAID," it always "WIPES OUT" the drives and re-creates the entire mirror! BAD, very BAD! There ALWAYS should be an option to add back a drive, if one goes bad, and Dell failed on this task, because there is NOT an easy way to do it!
There is "Manage Array" but no "manage secondary drive" option like you are mentioning.
And OMSA does not allow changing of the 2nd physical drive that has not yet been added to the array - just very weird - I am running W2k3 Server Standard R2 64-bit.