Back in the old days of networker 7.2 you can do a stage job from adv_file type disk to tape to free up pace on your disk from the GUI. I was told you can't anymore. You have to use the nsrstage command to get it done.
Can someone help me with the command syntax ?
I would like to stage all my savesat that is more than a month old to tape.
Check out the administration guide for your NetWorker version and look into the section on 'Staging Backups'. You can define a staging policy that will set a 'Max Storage Period' that defines the number of days a saveset will be on a volume before being staged. This looks like it's what you are looking for. There are also instructions in there on how to use the command line if you prefer that.
You can find the Admin Guide on Powerlink (for example for Networker 7.5.1)