Installation guide

Fig u re 1.14 . Creat in g Lo g ical Volu mes

1.7. Global Net work 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 1.15, “ 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.

⁠Chapt er 1 . Red Hat Clust er Suit e Overview