About limiting the size of unified and legacy logs
To limit the size of the NetBackup logs, specify the log size in the option in the NetBackup Administration Console. When the NetBackup log size grows up to this configuration value, the older logs are deleted. To set the log size in GB, select the check box, which lets you select the value in GB from the drop-down list.
See About log retention in NetBackup.
You can specify the setting under Host Properties in the Logging dialog box in the NetBackup Administration Console.
Note:
You can verify the log pruning behavior in NetBackup by creating the following directories:
On Windows: install_path\NetBackup\logs\nbutils
On UNIX: /usr/openv/netbackup/logs/nbutils