After adding larger drives to an original 4 bay Drobo a warning message popped up my WinXP PC on start-up stating:
[i]"Drobo has detected a new unformatted volume. Would you like to format the new volume?
“[Note: Any existing volumes will remain unchanged during this process.]”[/i]
Whilst its worrying that formatting usually overwrites existing information, in this case formatting retains all the existing information and formats only the additional drive space added, making it available for use. Under normal circumstances this sort of warning wouldn’t show - only - because WinXP can only work with 2TB Volumes means that the additional drives need to be formatted as an additional volume.
After formatting and choosing a designated drive letter for the new volume, the additional space becomes available for use on the Drobo volume without any drive letter switching neccessary to access it.
I should have been less worried and paid more attention to:
“[Note: Any existing volumes will remain unchanged during this process.]”