Editing Cluster and its component Understanding (section)

== ⁠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 [https://access.redhat.com/documentation/en-US/Red_Hat_Enterprise_Linux/5/html-single/Cluster_Suite_Overview/index.html#fig-gnbd-overview-CSO 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. 

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[[Image:GNBD-overview.png]]

'''Figure&nbsp;1.15.&nbsp;GNBD Overview'''