Reducing Backup Time

[01:19:50]$ /backup_restore/backupDatabase -b 128 -s 45056000 -non-interactive

The above command is usually ran through cron on a daily basis. However it takes 2hrs to complete. The tape is usually inserted into the V890 server, and cron kicks off the backup around 1:10AM. It completes around 3:30 - 345AM. I'm not really sure what the numbers are representing, but would it be possible to reduce the time it takes for the backup to complete?