Red Hat GNBD WITH GLOBAL FILE SYSTEM IN RHEL 4.5 Configuration And Administration Manual page 11

Note
A server should not import the GNBDs to use them as a client would. If a server
exports the devices uncached, the underlying devices may also be used by
Usage
gnbd_export -dpathname-egnbdname [-c][-u][-U
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 a network.
-o
Export the device as read-only.
-c
Enable caching. Reads from the exported GNBD and takes advantage of the Linux page
cache.
By default, the
gnbd_export
Warning
When you configure GNBD servers with device-mapper multipath, do not spe-
cify the
-c
logical volume must run with caching disabled.
Note
If you have been using GFS 5.2 or earlier and do not want to change your GN-
BD setup you should specify the
caching was enabled by default for
GNBD runs with a noticeable performance decrease. Also, if the
specified, the exported GNBD runs in timeout mode, using the default timeout
value (the
Usage
command does not enable caching.
option, as this lead sto data corruption. All GNBDs that are part of a
-c
option). For more information about the
-t
4
option. Before GFS Release 5.2.1, Linux
. If the option is not specified,
gnbd_export -c
gnbd_export
.
gfs
option is not
-c
command and