how to duplicate the Netbackup media tape backup to another media tape ?

(there is some automated if you need to do it all the time)

By hand.

If the tape needs to be imported do that first
Phase 1 and Phase 2

Once the source tape is a valid tape with images in netbackup

in the GUI
go to Catalog
in the action pull down choose duplicate ( this means look for items that qualify for duplication)
in media id put in the id of the source tape.
in date range start back in 2000 or some date you know is before the images on the tape ( as you are only searching this one tape it will not find a lot)
now hit the search button

Once it comes back in the bottom with all the images on the tape. pick all or just the ones you want to duplicate.

right click the highlighted ones and choose duplicate

in the new screen
Say how many copies you want
check mark if you want the dup tape to become the primary
choose a storage unit
choose a volume pool - try to choose a pool OTHER than the one the source tape is in - as it might try to dup the tape to the same tape.
your choice to keep or change the retention
 if you keep multiplexing it will go faster, if you do not keep it it will take longer to dup.

(my quick responce - hope you understand it)