Red Hat GFS 5.2.1 -, Руководство администратора

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Chapter 11. Using GNBD 115
The GNBD driver is implemented through the following client and server kernel modules.
• gnbd.o
— Implements the GNBD device driver on GNBD clients (nodes using GNBD devices).
• gnbd_serv.o
— Implements the GNBD server. It allows a node to export local storage over the
network.
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.
11.2.1. Exporting a GNBD from a Server
The
gnbd_serv.o
kernel module must be loaded on a node before it can export storage as a GNBD.
Once local storage has been identified to be exported, the
gnbd_export
command is used to export
it.
Caution
When configured for GNBD multipath, a GNBD server (a server that is exporting a GNBD) ignores
Linux page caching. Caching is ignored to ensure data integrity when using GNBD multipath. (By
default, the
gnbd_export
command exports with caching turned off.)
Note
A server should not use the devices it has exported, nor should it import the GNBDs to use them as
a client would.
11.2.1.1. Usage
gnbd_export -d pathname -e gnbdname [
-c
] [
-P
PortNumber
]
pathname
Specifies a storage device to export.
gnbdname
Specifies an arbitrary name selected for the GNBD. It is used as the device name on GNBD
clients. This name must be unique among all GNBDs exported in the network.
-c
Enable caching. Reads from the exported GNBD and takes advantage of the Linux page cache.
By default, the
export_gnbd
command does not enable caching.