Installation guide

multicast addressing and IGMP are enabled. Without multicast and IGMP, not all nodes can

participate in a cluster, causing the cluster to fail.

Note

Procedures for configuring network switches and associated networking

equipment vary according each product. Refer to the appropriate vendor

documentation or other information about configuring network switches and

associated networking equipment to enable multicast addresses and IGMP.

8. Considerations for Using Conga

When using Conga to configure and manage your Red Hat Cluster, make sure that each

computer running luci (the Conga user interface server) is running on the same network that

the cluster is using for cluster communication. Otherwise, luci cannot configure the nodes to

communicate on the right network. If the computer running luci is on another network (for

example, a public network rather than a private network that the cluster is communicating on),

contact an authorized Red Hat support representative to make sure that the appropriate host

name is configured for each cluster node.

9. General Configuration Considerations

You can configure a Red Hat Cluster in a variety of ways to suit your needs. Take into account

the following considerations when you plan, configure, and implement your Red Hat Cluster.

No-single-point-of-failure hardware configuration

Clusters can include a dual-controller RAID array, multiple bonded network channels,

multiple paths between cluster members and storage, and redundant un-interruptible power

supply (UPS) systems to ensure that no single failure results in application down time or

loss of data.

Alternatively, a low-cost cluster can be set up to provide less availability than a

no-single-point-of-failure cluster. For example, you can set up a cluster with a

single-controller RAID array and only a single Ethernet channel.

Certain low-cost alternatives, such as host RAID controllers, software RAID without cluster

support, and multi-initiator parallel SCSI configurations are not compatible or appropriate for

use as shared cluster storage.

Data integrity assurance

To ensure data integrity, only one node can run a cluster service and access cluster-service

data at a time. The use of power switches in the cluster hardware configuration enables a

node to power-cycle another node before restarting that node's cluster services during a

failover process. This prevents two nodes from simultaneously accessing the same data

Considerations for Using Conga