Use the following information to evaluate the best quorum configuration for your topology:
Do you have a device that is capable of being connected to all Solaris hosts of the cluster?
If yes, configure that device as your one quorum device. You do not need to configure another quorum device because your configuration is the most optimal configuration.
If you ignore this requirement and add another quorum device, the additional quorum device reduces your cluster's availability.
If no, configure your dual-ported device or devices.
Ensure that the total number of votes contributed by quorum devices is strictly less than the total number of votes contributed by nodes. Otherwise, your nodes cannot form a cluster if all disks are unavailable, even if all nodes are functioning.
In particular environments, you might want to reduce overall cluster availability to meet your needs. In these situations, you can ignore this best practice. However, not adhering to this best practice decreases overall availability. For example, in the configuration that is outlined in Atypical Quorum Configurations the cluster is less available: the quorum votes exceed the node votes. In a cluster, if access to the shared storage between Host A and Host B is lost, the entire cluster fails.
See Atypical Quorum Configurations for the exception to this best practice.
Specify a quorum device between every pair of hosts that shares access to a storage device. This quorum configuration speeds the fencing process. See Quorum in Greater Than Two–Host Configurations.
Quorum devices slightly slow reconfigurations after a node joins or a node dies. Therefore, do not add more quorum devices than are necessary.