Installation guide

Warning
This option should only be used for exporting shared storage devices, when the -U
command option does not work. T his should almost never happen for SCSI devices. If two
GNBD devices are not exporting the same underlying device, but are given the same
UID, data corruption will occur.
-U Command
Gets the UID command. T he UID command is a command the gnbd_export command will run
to get a Universal Identifier for the exported device. T he UID is necessary to use device-mapper
multipath with GNBD. The command must use the full path of any executeable that you wish to
run. A command can contain the %M, %m or %n escape sequences. %M will be expanded to
the major number of the exported device, %m will be expaned to the minor number of the
exported device, and %n will be expanded to the sysfs name for the device. If no command is
given, GNBD will use the default command /usr/sbin/gnbd_get_uid. T his command will
work for most SCSI devices.
Examples
This example is for a GNBD server configured with GNBD multipath. It exports device /dev/sdc2 as
GNBD gam m a. Cache is disabled by default.
gnbd_expo rt -d /dev/sdc2 -e gamma -U
This example is for a GNBD server not configured with GNBD multipath. It exports device /dev/sdb2 as
GNBD delta with cache enabled.
gnbd_expo rt -d /dev/sdb1 -e delta -c
This example exports device /dev/sdb2 as GNBD delta with cache enabled.
gnbd_expo rt -d /dev/sdb2 -e delta -c
3.2. Importing a GNBD on a Client
The gnbd.ko kernel module must be loaded on a node before it can import GNBDs. When GNBDs are
imported, device nodes are created for them in /dev/gnbd/ with the name assigned when they were
exported.
Usage
gnbd_import -i Server
Server
Specifies a GNBD server by hostname or IP address from which to import GNBDs. All GNBDs
exported from the server are imported on the client running this command.
Red Hat Enterprise Linux 4 Global Network Block Device
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