How to caliculate that,how many tape volumes…
Are you asking how to find out how many were used for a backup? Or do you want to calculate how many are expected to be used in the future?
Since you’re using BRMS, the WRKMEDBRM command is good for learning things about volumes that were used in the past.
But as far as I know, the only calculations you can make for the future would be based on keeping a history of how things worked on your system in the past. The history should include which SAVxxx commands were run, the number, sizes and types of the objects saved by each command, the type of tape equipment used and the specs of the tape volumes.
After you have enough history to cover most future scenarios, you could begin forecasting estimates of how many volumes a given future backup might take.
I need to find out how many tapes were used for a backup on a particular day?