Global Network Block Device - Red Hat ENTERPRISE LINUX 4 Manual

Chapter 1. Red Hat Cluster Suite Overview
Figure 1.18. Creating Logical Volumes

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
Figure 1.19, "GNBD Overview". Multiple GNBD clients can access a device
or SAN storage). Refer to
exported by a GNBD server, thus making a GNBD suitable for use by a group of nodes running GFS.
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