About the auto-discovery streaming mode
The auto-discovery streaming mode is initiated if the NEW_STREAM directive is not the first line of the backup selections list. The list must contain either the ALL_LOCAL_DRIVES directive or wildcards.
In this mode, the backup selections list is sent to the client, which preprocesses the list and splits the backup into streams as follows:
If the backup selections list contains the ALL_LOCAL_DRIVES directive, NetBackup backs up the entire client. However, NetBackup splits each drive volume (Windows) or file system (UNIX) into its own backup stream.
If wildcards are used, the expansion of the wildcards results in one stream per wildcard expansion. Wildcard usage is the same as for Windows clients.
If the backup selections list contains neither the ALL_LOCAL_DRIVES directive nor wildcards, the auto-discovery mode is not used. The server preprocesses rather than the client. Each file path in the backup selections list becomes a separate stream.
The auto-discovery streaming mode applies to Standard and MS-Windows policy types.
Before the backup begins, the client uses auto-discovery to preprocess the backup selections list to determine how many streams are required. The first backup that a policy performs preprocesses the backup selections list. Depending on the length of the preprocess interval, preprocessing may not occur before every backup.