After identifying the cluster hardware components described in
Choosing a Hardware Configuration, set up the basic
cluster hardware and connect the nodes to the optional console
switch and network switch or hub. Follow these steps:
In all nodes, install the required network adapters and host bus
adapters. Refer to Section 2.3.1
Installing the Basic Cluster Hardware for more
information about performing this task.
Set up the optional console switch and connect it to each node.
Refer to Section 2.3.3
Setting Up a Console Switch for more information about
performing this task.
If a console switch is not used, then connect each node to a
Set up the network switch or hub and use network cables to
connect it to the nodes and the terminal server (if applicable).
Refer to Section 2.3.4
Setting Up a Network Switch or Hub for more information
about performing this task.
After performing the previous tasks, install Red Hat Enterprise
Linux as described in Section 2.4
Installing and Configuring Red Hat Enterprise Linux.
Nodes must provide the CPU processing power and memory required
In addition, nodes must be able to accommodate the SCSI or Fibre
Channel adapters, network interfaces, and serial ports that the
hardware configuration requires. Systems have a limited number of
pre-installed serial and network ports and PCI expansion slots.
helps determine how much capacity the node systems employed
|Cluster Hardware Component
|SCSI or Fibre Channel adapter to shared disk storage
||One for each bus adapter
|Network connection for client access and Ethernet heartbeat
||One for each network connection
|Point-to-point Ethernet connection for 2-node clusters
||One for each connection
|Terminal server connection (optional)
Table 2-10. Installing the Basic Cluster Hardware
Most systems come with at least one serial port. If a system has
graphics display capability, it is possible to use the serial
console port for a power switch connection. To expand your serial
port capacity, use multi-port serial PCI cards. For multiple-node
clusters, use a network power switch.
Also, ensure that local system disks are not on the same SCSI
bus as the shared disks. For example, use two-channel SCSI
adapters, such as the Adaptec 39160-series cards, and put the
internal devices on one channel and the shared disks on the other
channel. Using multiple SCSI cards is also possible.
Refer to the system documentation supplied by the vendor for
detailed installation information. Refer to Appendix A Supplementary Hardware
Information for hardware-specific information about using
host bus adapters in a cluster.
In a cluster, shared disks can be used to store cluster service
data. Because this storage must be available to all nodes running
the cluster service configured to use the storage, it cannot be
located on disks that depend on the availability of any one
There are some factors to consider when setting up shared disk
storage in a cluster:
It is recommended to use a clustered filesystem such as Red Hat
GFS to configure Red Hat Cluster Manager storage resources, as it
offers shared storage that is suited for high-availability cluster
services. For more information about installing and configuring Red
Hat GFS, refer to the Red Hat GFS
Whether you are using Red Hat GFS, local, or remote (NFS)
storage, it is strongly recommended that
you connect any storage systems or enclosures to redundant UPS
systems for a highly-available source of power. Refer to Section 2.5.3
Configuring UPS Systems for more information.
The use of software RAID or Logical Volume
Management (LVM) for shared
storage is not supported. This is because these products do not
coordinate access to shared storage from multiple hosts. Software
RAID or LVM may be used on non-shared storage on cluster nodes (for
example, boot and system partitions, and other file systems which
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 access to data
and possible corruption.
For remote filesystems 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
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
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 126.96.36.199
Creating File Systems.
After setting up the shared disk storage hardware, partition the
disks and create file systems on the partitions. Refer to Section 188.8.131.52
Partitioning Disks, and Section 184.108.40.206
Creating File Systems for more information on
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
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
A network switch or hub, although not required for operating a
two-node cluster, can be used to facilitate cluster and client
system network operations. Clusters of more than two nodes require
a switch or hub.
Set up a network switch or hub according to the documentation
provided by the vendor.
After setting up the network switch or hub, connect it to each
node by using conventional network cables. A terminal server, if
used, is connected to the network switch or hub through a network