vcbmounter will only allow once session (vcbmounter to execute) at a time. So, all vcb backups must occur serially (one after another). I do not know if this is a hardware or software limitation.

So, what we do is run vcbmounter to export all our guests to their respective directories. Then, we run the "subst" command to assign drive letters to the various directories. Finally, we kick off two TSM backups to put the vcb images to tape. The "subst" of directories for drives allows us to put our backups on different tapes so during a restore we avoid tape contention. Overall, it works great.

Ray