Sun Cluster configurations use quorum devices to maintain data and resource integrity. If the cluster temporarily loses connection to a node, the quorum device prevents amnesia or split-brain problems when the cluster node attempts to rejoin the cluster. You configure quorum devices by using the scsetup(1M) utility.
You do not need to configure quorum devices for a single-node cluster.
Consider the following points when you plan quorum devices.
Minimum – A two-node cluster must have at least one shared disk assigned as a quorum device. For other topologies, quorum devices are optional.
Odd-number rule – If more than one quorum device is configured in a two-node cluster, or in a pair of nodes directly connected to the quorum device, configure an odd number of quorum devices. This configuration ensures that the quorum devices have completely independent failure pathways.
Connection – You must connect a quorum device to at least two nodes.
For more information about quorum devices, see “Quorum and Quorum Devices” in Sun Cluster Concepts Guide for Solaris OS and “Quorum Devices” in Sun Cluster Overview for Solaris OS.