After I posted the message, I did a poweroff, unplug all the HD and plug in again, Both drivers are seen by the system. Don't know why it happened.
When I first installed my Valkyrie, I only have one HD drive. Recently I got 2nd HD. But after I plugged in, I don't see it in the Vakyrie DISK MANAGEMENT.
Is there anything I should do to let Valkyrie see the 2nd drive?