Red Hat GFS 6.1 -, Administrator'S Manual

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Chapter 6.
Using GNBD with Red Hat GFS
GNBD (Global Network Block Device) provides block-level storage access over an Eth-
ernet LAN. GNBD components run as a client in a GFS node and as a server in a GNBD
server node. A GNBD server node exports block-level storage from its local storage (either
directly attached storage or SAN storage) to a GFS node.
This chapter describes how to use GNBD with Red Hat GFS and consists of the following
sections:
•
Section 6.1 GNBD Driver and Command Usage
•
Section 6.2 Running GFS on a GNBD Server Node
Note
Multipath GNBD is not available with Red Hat GFS 6.1. That is, device mapper multipath
(
dm-multipath
) cannot use GNBD. GNBD without multipath is available.
6.1. GNBD Driver and Command Usage
The Global Network Block Device (GNBD) driver allows a node to export its local storage
as a GNBD over a network so that other nodes on the network can share the storage. Client
nodes importing the GNBD use it like any other block device. Importing a GNBD on
multiple clients forms a shared storage configuration through which GFS can be used.
The GNBD driver is implemented through the following components.
• gnbd_serv
— Implements the GNBD server. It is a user-space daemon that allows a
node to export local storage over a network.
• gnbd.ko
— Implements the GNBD device driver on GNBD clients (nodes using GNBD
devices).
Two user commands are available to configure GNBD:
• gnbd_export
(for servers) — User program for creating, exporting, and managing
GNBDs on a GNBD server.