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.
•
gnbd_import
(for clients) — User program for importing and managing GNBDs on a GNBD
client.
1. Exporting a GNBD from a Server
The
gnbd_serv
daemon must be running on a node before it can export storage as a GNBD.
You can start the
gnbd_serv
daemon running
gnbd_serv
as follows:
#gnbd_serv
gnbd_serv: startup succeeded
Once local storage has been identified to be exported, the
gnbd_export
command is used to
export it.
Note
When you configure GNBD servers with device-mapper multipath, you must not
use page caching. All GNBDs that are part of a logical volume must run with
caching disabled. By default, the
gnbd_export
command exports with caching
turned off.
Chapter 3.
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