Posting this for posterity since I just had to research it.
We'd had an issue with a Dell PowerEdge (PE) 2950 yesterday in which one of the drives had failed. Using Dell OpenManage 5.4 (a/k/a Server Admin) the virtual disk (RAID 5) the failed physical was part of displayed as "Degraded" before replacement.
After replacement and automatic rebuild the virtual disk displayed as "Ready" and the failed physical had returned to "Online". I got a question saying the status should be "Optimal" rather than "Ready" from support engineer. In review of notes on a different PE 2950 I'd had issue on before I saw that it had in fact shown me "Optimal" after rebuild for the virtual. However on checking its Dell OpenManage (which is version 5.2) it shows the virtual as "Ready" rather than "Optimal". My notes show that at the time I saw "Optimal" previously I was looking at the controller's BIOS (i.e. I had interrupted boot to go into the BIOS of the PERC itself) rather than at Dell OpenManage.
I reasoned the issue is simply that the PERC BIOS and the Dell OpenManage show different names for the same status. On researching that I found this is indeed the case:
On checking the documentation link for the 5.4 OpenManage on the system that had the issue it shows “Ready” as a valid state for Virtual disks but not “Optimal”. It says “Ready” means it is functioning normally.
I see the same thing for the 5.2 OpenManage I’m running on the other 2950 I mentioned and also see this in later versions of OpenManage.
However, on checking the document for BIOS for PERC 5/i it shows “Optimal” as a valid status but not “Ready”.
So it does appear this is simply a difference in the way BIOS and OpenManage show the same state.