Installation guide

Chapter 2. Hardware Installation and Operating System Configuration 21
cluster nodes (for example, boot and system partitions, and other file systems that are
not associated with any cluster services).
An exception to this rule is CLVM, the daemon and library that supports clustering of
LVM2. CLVM allows administrators to configure shared storage for use as a resource
in cluster services when used in conjunction with the CMAN cluster manager and the
Distributed Lock Manager (DLM) mechanism for prevention of simultaneous node ac-
cess to data and possible corruption. In addition, CLVM works with GULM as its cluster
manager and lock manager.
• For remote file systems such as NFS, you may use gigabit Ethernet for
improved bandwidth over 10/100 Ethernet connections. Consider redundant
links or channel bonding for improved remote file system availability. Refer to
Section 2.5.1 Configuring Ethernet Channel Bonding for more information.
• Multi-initiator SCSI configurations are not supported due to the difficulty in obtaining
proper bus termination. Refer to Appendix A Supplementary Hardware Information for
more information about configuring attached storage.
• A shared partition can be used by only one cluster service.
• Do not include any file systems used as a resource for a cluster service in the node’s
local /etc/fstab files, because the cluster software must control the mounting and
unmounting of service file systems.
• For optimal performance of shared file systems, make sure to specify a 4 KB block size
with the mke2fs -b command. A smaller block size can cause long fsck times. Refer
to Section 2.5.3.2 Creating File Systems.
After setting up the shared disk storage hardware, partition the disks and create
file systems on the partitions. Refer to Section 2.5.3.1 Partitioning Disks, and
Section 2.5.3.2 Creating File Systems for more information on configuring disks.
2.3.3. Setting Up a Console Switch
Although a console switch is not required for cluster operation, it can be used to facilitate
node management and eliminate the need for separate monitors, mouses, and keyboards
for each cluster node. There are several types of console switches.
For example, a terminal server enables connection to serial consoles and management of
many nodes from a remote location. For a low-cost alternative, use a KVM (keyboard,
video, and mouse) switch, which enables multiple nodes to share one keyboard, monitor,
and mouse. A KVM switch is suitable for configurations in which GUI access to perform
system management tasks is preferred.
Set up the console switch according to the documentation provided by the vendor.
After the console switch has been set up, connect it to each cluster node. The cables used
depend on the type of console switch. For example, a Cyclades terminal server uses RJ45
to DB9 crossover cables to connect a serial port on each node to the terminal server.