Named disk sets created in a Sun Cluster environment are called multi-owner disk sets. Multi-owner disk sets allow multiple nodes to share the ownership of the disk sets and to simultaneously access the shared disks. All disks and volumes in a multi-owner disk set can be directly accessed by all the nodes in a cluster. Each multi-owner disk set contains a list of hosts that have been added to the disk set. Consequently, each multi-owner disk set within a cluster configuration can have a different (and sometimes overlapping) set of hosts.
Each multi-owner disk set has a master node. The function of the master node is to manage and update the state database replica changes. Since there is a master node per disk set, multiple masters can exist simultaneously. There are two ways that the master is chosen. The first way is that a node becomes the master if it is the first node to add a disk to the disk set. The second way is when a master node panics and fails. The node with the lowest node id becomes the master node.
Multi-owner disk set functionality is enabled only in a Sun Cluster environment to manage multi-owner disk set storage. The Solaris Volume Manager for Sun Cluster feature works with releases of Sun Cluster beginning with the Sun Cluster 10/04 software collection and with applications like Oracle Real Applications Clusters. For more information on Solaris Volume Manager for Sun Cluster, see Chapter 4, Solaris Volume Manager for Sun Cluster (Overview).
Before you can configure multi-owner disk sets, the following software must be installed in addition to the Solaris OS:
Sun Cluster initial cluster framework
Sun Cluster Support for Oracle Real Application Clusters software
Oracle Real Application Clusters software
For information on setting up Sun Cluster and Oracle Real Application Clusters software, see Sun Cluster Software Installation Guide for Solaris OS and Sun Cluster Data Service for Oracle Real Application Clusters Guide for Solaris OS.