I have a Dell server that has 6 disks in 3 Raid 1 arrays. One disk was replaced and came up as 'Foreign' so I followed the process to clear it and now it shows 'Ready'. I need to add it back into the Raid 1 mirror for Virtual disk 1 as but it won't allow me to. In OMSA I have selected System->Storage->Virtual Disks. For the second virtual disk (which is showing Degraded) I have selected Assign/Unassign Dedicated Hot Spare and then Execute but I get a message that reads:

Storage Management only displays those disks that can be used as a hot spare. There are currently no disks that are available, large enough, or of the correct type to be used as a hot spare for this virtual disk

The disks are identical with the same product ID etc. I would just pop the disk out and back in as a test but it is in a data center so I am trying to use remote tools to fix the problem.