Summary
DPX jobs can back up several NetApp Filer volumes to a jukebox with several tape drives. However, NDMP version 4 disallows simultaneous data streaming to multiple tape drives. Only one drive can be used at a time.
Resolution
Currently, NDMP version 4 supports a single data stream only. Thus an NDMP job that backs up more than one filer volume cannot start multiple tasks to stream to multiple drives simultaneously.
The below excerpt from NDMP version 4 documentation further explains its secondary storage capabilities:
2.3.4.2. Tape Service
A tape service provides the NDMP interface to a secondary storage device, such as a tape drive or a writeable CD-ROM. The tape service reads or writes a single data stream, for backup or recovery respectively. Note that a tape service only handles the reading or writing of one "cartridge," a single tape or CD. The tape service will notify the DMA when a cartridge is read or written and the DMA will provide the necessary media management.
The ability to run concurrent data streams will likely be available in the next release of NDMP since the current working documentation for NDMP version 5 describes multiplexing.
For the most up-to-date information, visit www.ndmp.org.