Not a trivial question at all. fbackup must ALWAYS use a config file (the -f option) for modern tape drives. Here is an example of a useful config file:
blocksperrecord 4096
records 64
checkpointfreq 4096
readerprocesses 6
maxretries 5
retrylimit 5000000
maxvoluses 200
filesperfsm 2000
By using this config file, you should see a significant reduction in the backup time.
One of the options in the config file is the keyword chgvol which defines a script that you must write. The script will use the environment variable $LIBRARY to define the changer's device file. Creating this device file is very dependent on the version of HP-UX you are using.
Next, you become familiar with the mc command to manipulate the changer. Now it sounds simple to switch tapes but there are no assumptions. So your script must unload the tape and place it in an unused slot. Then it must select the next tape and load it into the changer. So far, so good. But if your backup needs 3 tapes, the same script will be called and you can't unload the tape into the first slot. So the script needs stored logic in the form of a status file that keeps track of what is happening.
So the script can't assume anything -- it will be run every time fbackup runs out of tape and needs another volume. The script also should be initialized prior to the start of fbackup so the desired first tape is loaded (and no unknown tape was left in the changer).
So you'll need some scripting skills to handle all the possible conditions. The script's requirements would then be integrated into your current backup script.
Bill Hassell, sysadmin
