Sun Cluster Overview for Solaris OS

Sun Cluster Software Environment

To function as a cluster member, a node must have the following software installed:

Figure 3–2 shows a high-level view of the software components that work together to create the Sun Cluster software environment.

Figure 3–2 Sun Cluster Software Architecture

Illustration: Sun Cluster software components such as the RGM, CMM, CCR, volume managers, and the cluster file system.

Cluster Membership Monitor

To ensure that data is safe from corruption, all nodes must reach a consistent agreement on the cluster membership. When necessary, the CMM coordinates a cluster reconfiguration of cluster services in response to a failure.

The CMM receives information about connectivity to other nodes from the cluster transport layer. The CMM uses the cluster interconnect to exchange state information during a reconfiguration.

After detecting a change in cluster membership, the CMM performs a synchronized configuration of the cluster. In this configuration, cluster resources might be redistributed, based on the new membership of the cluster.

The CMM runs entirely in the kernel.

Cluster Configuration Repository (CCR)

The CCR relies on the CMM to guarantee that a cluster is running only when quorum is established. The CCR is responsible for verifying data consistency across the cluster, performing recovery as necessary, and facilitating updates to the data.

Cluster File Systems

A cluster file system is a proxy between the following:

Cluster file systems are dependent on global devices (disks, tapes, CD-ROMs). The global devices can be accessed from any node in the cluster through the same file name (for example, /dev/global/). That node does not need a physical connection to the storage device. You can use a global device the same as a regular device, that is, you can create a file system on a global device by using newfs or mkfs.

The cluster file system has the following features: