We are currently in the midst of planning on Netbackup version upgrade. This upgrade will included the master server (clustered), media server (netbackup appliance) and clients.
On the master server (clustered), we are planning to perfrom the version upgrade with 2(two) option, which is:
1 - Upgrade the node one-by-one where the version upgrade on one node (passive) then the other node the next day.
2 - Upgrade the node one-by-one where the version upgrade on one node (active) and push install the other node in all one day.
The reason of 2 options are:
option 1: Let the jobs (backup,duplication,replication) ran as usual on the active node. After one node (passive) version upgraded, we will switch the role from passive node to active node and let jobs run over night and monitor how it goes and we will proceed with the other node.
option 2: Perform the version upgrade simultaneously on the active node and passive node but with down time estimated of 3-4 hours but save one day work.
We have done this previously during upgrade from version 7.6 to 7.7 with option 1 and intended the same way. But the option 2 were suggested by our partner. Given the options, which options is the best way?
In general option 2 is preferred and safer. Option 1 may cause you to break the NetBackup databasse.
During an upgrade there are often changes made to the NBDB schema and potentially upgrades to the NetBackup DB. Using option 1 seems to bypass those required steps (it may have worked for your 7.6 to 7.7 upgrade but that would be by chance only).
As @sdo says, you don't mention the target version you intend to upgrade to, but any recent version of NBU will most certainly update the database version on the master requiring you to use option 2.