What is the point with this qustion ?
Assumption is the mother of all mess ups.
If this post answered your'e qustion - Please mark as a soloution.
Nicolai, it wont hurt knowing how many storage units we can create having some number of drives at our disposal beforehand...also,its more of an inquisitiveness :)
One STU per media server per drive type per robot.
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Marriane,if you dont mind can you break it up with an example pls...
First off, (Taken from NBU AdminGuide volume I) Storage Unit is a label that NetBackup associates with physical storage. The storage can identify a robot, a path to a volume, or a disk pool. A Storage units can be included as part of a storage unit group or a storage lifecycle policy.
Storage Unit types:
Now, to elaborate what Marianne answered:
# of STU = 1 STU/Media Server/STU Type/per robot
Since there is no 1:1 relation between physical devices and storage units you can create so many storage units that you can confuse the admin before Netbackup.
That does not provide a definite number - but try to keep a 1:1 ration as rule of thump. This does not always work - e.g if you do duplication where you may have two storage unit pointing to the tape tape devices but different "concurrent write drives".
As per Nicolai's excellent post, there is no 1:1 relationship between STUs and devices, merely device type (drive density) and location (robot number and media server).
So, some examples: