NT 4.0 server disk mirroring

[floyd]

hey everyone. i am running NT 4.0 server and i am using disk mirroring. problem is, when i remove the master disk to simulate a hard drive crash, the drive that has been mirrored will not boot up. i get "operation systems not found". i am 100% sure that the jumpers are correct and that the drive is active using fdisk.
i am at a loss. any help will be appreciated.
thank you
floyd.
my email is michaelL@imsi.com