Improving NetBackup backup performance
If backups are running slowly, check to see if the database has an excessive workload. BLI backups allow hot database backups and quick freeze database backups. Because the database is running during both of these backup methods while NetBackup is backing up the database files, Oracle I/O can affect the backup performance.
If the database is not running with a high transaction volume, troubleshoot NetBackup. If the incremental backup takes a long time to finish, it could mean that there are more changed blocks since the last incremental backup. Verify whether the size of the incremental backup image has increased, and consider increasing the frequency of incremental backups.
Finally, you can improve the speed at which backup is performed by using multiplexed backups. Assigning multiple policies to the same backup device is helpful when devices are not writing at their maximum capacity.