The architecture of a Backup Server is shown below. Each Backup Server contains both a Catalog Server and a Media Server, as well as two interfaces that manage administrator input. The Catalog Server manages the index associated with Backup Sets, accepts user input, and controls the transfer of data among the Catalog Server, the Media Server, any NDMP Server, and Backup Agents.
Typically, both the Catalog Server and Media Server are deployed on the same computer. However, a Media Server can also be installed with a Backup Agent to permit LAN-free backups. We describe this configuration as the Remote Storage Option
. Note that disjointed Catalog Servers and Media Servers must be LAN-connected, unless backup replication is used. Backup Replication Servers
copy Backup Sets from one Backup Server to another, whether over a LAN or a WAN.
Catalog Server Options
An additional option for the Catalog Servers is the NDMP Option
which allows Backup Servers to back up and restore data from any device that supports the NDMP protocol, such as network-attached storage (NAS). In effect, these NDMP-compliant devices are data sources that do not require Backup Agent software.
Media Server Options
Other options for the Media Server include the Shared Storage Option, Tape Duplication, and Disk-to-Tape. The Shared Storage Option
allows a single SAN-attached tape drive or tape library to be shared among multiple Backup Servers. Tape Duplication allows tapes to be quickly and exactly duplicated. Disk-to-Tape permits disk-based virtual tape library (VTL) Backup Sets to be copied to tape devices.