This is not possible within vault.
The best you could do would be to reduce the number of partially full media in the volume pool. This would give a better chance of tapes becoing fully as less can be used at once.
The problem with this, is it reduces the number of drives that can will be used at once for the vault jobs, to the same value as 'partially full media'.
I have a couple of suggestions to add this feature, back when we could add "IDEAS" - nothing ever came of it.
So, I figured out how to do it.
I do this every week, since I have long term (1 year, 7 year and infinite ) tapes I prefer to send offsite only when full.
However, it is a multi step process.
Create a long term vault - I named mine friday.vault because I am so creative.
Create a Volume Group called Friday vault (again with the creativity ) - I put my expired cleaning tapes here to hold it open.
I set my friday.vault to only vault from the long term pools, (I separate my daily vault and long term vault pools for doing this easily) but, if you are all in one pool, you just stop writing for a bit.
Step 1. review processes to ensure nothing is writing to these tapes - it ends with error 288 if you do not do this, but there are no other real issues, except it may vault that tape if the timing is off.
Step 2. Go to the volume pools you are vaulting, and use MOVE to update the active partially full tapes as out of the robot in the Friday Volume Group.
Step 3. Run the vault, since the partially full tapes are virtually NOT IN THE ROBOT, it will not vault them.
Step 4. once the vault is complete, inventory the robot, it will magically discover all the partially full tapes were in fact in the robot the whole time, and mark them as in the robot and available for use.
WARNING - you must NOT let anyone run an inventory during this process, because it will move the partially full tapes logically back into the robot!
This works very well, I have several long term pools with NO partially full vaulted tapes.
The down side is there is NO way within netbackup to consolidate tapes, short of manually copying the images, and since it tries to roll from one tape to the next, you may end up running through a whole chain of tapes to get rid of an extra partially full tape. Either hat or wait for the images to expire - my infinite pool is the only one I cannot get rid of the partially full tapes.
In reference to the 1 or 2 above, they are the number of simultaneous tapes it will write to.
Theoretically, if you create a new pool and set the max partially full to 1 there will only ever be one partially full tape.
However - if you have multiple media servers, it can sometimes add tapes, and then you are stuck with an extra one.
This also limits your throughput, since writing to 6 tapes sends more data than to 1.