Netbackup License keys

you mean i have to purchase licenses for master servers as well?? but master servers are in the same cluster so i think i can use same license for the same cluster nodes??

License is needed for clusrer nodes altough those are inactive or standby state unless the node is deployed in cold DR site. Nodes in Cold DR site is subject of Cold DR license policy which allows users to use one additional copy of license.
Otherwise, if you deployed standby nodes in same site, I believe these nodes are not subject of Cold DR license policy.

kindly make it simple please i can not understand your point, please help me i am repeating my question:

two master server are clustered using microsoft clustering now in need to add one more master server in same cluster so do need need any more licenses or i can use same license key all server  are on the same site

NBU license could be based on

• number of host
• traffic flow (lan or san)
• processor could be considered as well

Each License is limited to Certain number of Master, Media and Client Server.

And Capacity based License is also available based on the data you backup.