Hello

In the event of a foreign configuration you have two options, import or clear. Clear will attempt to delete any virtual disk information from all foreign disks on the controller and bring them to a ready state. Import will attempt to update the virtual disk information on the controller with information from the foreign disk in an attempt to bring the disk back online. If the virtual disk is in any online or degraded state you should not import. Import should only be used if the virtual disk is in an offline or failed state.

You should be able to clear the foreign configuration, replace the disk, and let the replacement rebuild. You can find more information in the PERC manual.

http://www.dell.com/storagecontrollermanuals/

Thanks