-- Updated for clarity --
Are you saying CrashPlan will not back-up and restore a virtual drive? I will need to move my 6TB+ of files into the virtual drive in the same folder structure (eg Movies, Photos) and I will expect CrashPlan to scan through those without re-uploading them.
Also, restoring sounds like another issue. When a drive fails, I know "Photos" and "Movies" are gone and need to restore those folders. But here it sounds like random files just go missing and you have no way to know which ones need a Restore, and the only option would be to restore everything which would take a year.