Information in the Profile init<DBSID>.sap 

A requirement for using the Parallel Server option is that the database is installed on raw devices. The backup then runs via the dd command. Therefore make sure that the parameters dd_flags and dd_in_flags, which specify the required dd command, are set. See Supporting the Raw Device Configuration with BRBACKUP and BRRESTORE.

This parameter defines the instances running in parallel to the DDB instance. See parallel_instances.

The local (DDB) instance must not appear in the list of instance descriptions.

A BRARCHIVE archivation on the hard disk is required when archiving according to the mixed scenario (see Mixed Scenario). See archive_copy_dir.