We are maintaing incrimental backup proceedure if the catridge is full we remove the that media and replaces with new empty media like the process goes.
Here my qusetion is "is the data in the removed catridge is valid or not" and how can retrieve the data from the removed catridge
it is a removed catridge (6.25TB) ,
The ONLY thing that determines if data is valid or not, is the Retention Level/Period that you have selected in the Policy Schedule(s).
The location of the tapes does not matter.
If you start a restore and the tape is not in the robot, you will be prompted in Activity Monitor to insert the tape.
Yes, infinite retention backup data will be retained (indexed / catalogued) within a NetBackup environment forever. If you remove the tape cartridge from the drive(s)/library then you will obviously need to put the tape cartridge back inside the drive(s)/library in order to be able to actually restore anything.
N.B: my advice is to physically write protect the tape cartridge if/when you remove it for safe keeping.