Network Data Management Protocol (NDMP) technology should be used for backup if:
a network attached storage (NAS) appliance is required.
the use of TCP/I P must be avoided.
file permissions that can not be handled by legacy backup systems must be backed up.
backup consistency over several related data volumes must be ensured.
NDMP defines three kind of services: a data service that interfaces with the primary storage to be
backed up or restored, a tape service that interfaces with the secondary storage (primarily a tape
device), and a translator service performing translations including multiplexing multiple data
streams into one data stream and vice versA. NDMP services interact with each other. The result
of this interaction is the establishment of an NDMP control session if the session is being used to
achieve control for the backup or restore operation. It would result in an NDMP data session if the
session is being used to transfer actual file system or volume data (including metadata). Control
sessions are always TCP/IP-based, but data streams can be TCP/lP-or SAN-based. NDMP is more
or less NAS-centric and defines a way to back up and restore data from a device, such as a NAS
appliance, on which it is difficult to install a backup software agent, in the absence of NDMP, this
data must be backed up as a shared drive on the LAN, which is accessed via network file protocols,
such as Common Internet File System (CIFS) or Network File System (NFS), degrading backup
performance. NDMP works on a block level for transferring payload data (file content)but metadata
and traditional file system information needs to be handled by legacy backup systems that initiate
NDMP data movement. NDMP does not know about nor takes care of consistency issues regarding
related volumes (e.g., a volume to store data