1.7. Global Network Block Device
1.7. Global Network Block Device Global Network Block Device (GNBD) provides block-device access to Red Hat GFS over TCP/IP. GNBD is similar in concept to NBD; however, GNBD is GFS-specific and tuned solely for use with GFS. GNBD is useful when the need for more robust technologies - Fibre Channel or single-initiator SCSI - are not necessary or are cost-prohibitive. GNBD consists of two major components: a GNBD client and a GNBD server. A GNBD client runs in a node with GFS and imports a block device exported by a GNBD server. A GNBD server runs in another node and exports block-level storage from its local storage (either directly attached storage or SAN storage). Refer to Figure 1.19, "GNBD Overview" . Multiple GNBD clients can access a device exported by a GNBD server, thus making a GNBD suitable for use by a group of nodes running GFS. Figure 1.19. GNBD Overview