Importing A Gnbd On A Client; Considerations For Using Gnbd Multipath; Linux Page Caching - Red Hat GFS 6.0 Administrator's Manual

Chapter 11. Using GNBD
11.1.1.2. Examples
This example is for a GNBD server configured with GNBD multipath. It exports device
as GNBD . Cache is disabled by default.
gamma
gnbd_export -d /dev/sdc2 -e gamma
This example is for a GNBD server not configured with GNBD multipath. It exports device
as GNBD
/dev/sdb2
gnbd_export -d /dev/sdb1 -e delta -c

11.1.2. Importing a GNBD on a Client

The kernel module must be loaded on a node before it can import GNBDs. When GNBDs
gnbd.o
are imported, device nodes are created for them in
were exported.
11.1.2.1. 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.
11.1.2.2. Example
This example imports all GNBDs from the server named
gnbd_import -i nodeA

11.2. Considerations for Using GNBD Multipath

GNBD multipath allows you to configure multiple GNBD server nodes (nodes that export GNBDs to
GFS nodes) with redundant paths between the GNBD server nodes and storage devices. The GNBD
server nodes, in turn, present multiple storage paths to GFS nodes via redundant GNBDs. With GNBD
multipath, if a GNBD server node becomes unavailable, another GNBD server node can provide GFS
nodes with access to storage devices.
If you are using GNBD multipath, you need to take the following into consideration:

Linux page caching

•
Lock server startup
•
CCS file location
•
Fencing GNBD server nodes
•
with cache enabled.
delta
with the name assigned when they
/dev/gnbd/
.
nodeA
123
/dev/sdc2