VMS Disk Status: HostUnavailable

I have just popped an ST225 disk into my MicroVAX II to see if it works and I get this status: Device Device Error Volume Free Trans Mnt Name Status Count Label Blocks Count Cnt MICRO1$DUA0: HostUnavailable 0 MICRO1$ sh dev micro1$dua0:/fu Disk MICRO1$DUA0:, device type RD51, is online, host not available, file- oriented device, shareable, available to cluster, error logging is enabled. Error count 0 Operations completed 0 Owner process "" Owner UIC [0,0] Owner process ID 00000000 Dev Prot S:RWED,O:RWED,G:RWED,W:RWED Reference count 0 Default buffer size 512 I have done a quick search on the web and all I can see is that it may be somehow related to clustering. Well, I netbooted the machine specifically because I wanted to check out the disk. I have done this many times before without issue. What does this status mean? Regards Rob