Availability Components

Availability components provide for near-continuous uptime for system service components and application components. The following Java ES availability components are described in this section:

• High Availability Session Store 4.4.3

• Sun Cluster 3.1 8/05 and Sun Cluster Agents 3.1

• Sun Cluster Geographic Edition 3.1 2006Q4

High Availability Session Store 4.4.3

Sun Java System High Availability Session Store (HADB) provides a data store that can be used to make application data available even in the case of failure. This capability is especially important for restoring state information associated with a client session. Without this capability, failure during a session requires that all operations be repeated when the session is reestablished.

The following Java ES components provide services that store session state information: Application Server, Access Manager, and Message Queue. However, Application Server is the only component that can use HADB services to maintain session state during failure.

The Java ES installer provides HADB as a single installable component. However, a server and a client subcomponent are both required to provide HADB services.

Sun Cluster 3.1 8/05 and Sun Cluster Agents 3.1

Sun Cluster components are supported on the Solaris platform only.

Sun Cluster software provides high availability and scalability services for Java ES and for applications based on the Java ES infrastructure.

A cluster is a set of loosely coupled computers (cluster nodes) that collectively provide a single client view of services, system resources, and data. Internally, the cluster uses redundant computers, interconnects, data storage, and network interfaces to provide high availability to cluster-based services and data. Sun Cluster software continuously monitors the health of member nodes and other cluster resources and uses the internal redundancy to provide near-continuous access to these resources even when failure occurs.

The Java ES installer provides the Sun Cluster Core subcomponent and the Sun Cluster Agents as separately installable components. The following Sun Cluster agents are included in Java Enterprise System.

HA in the following list stands for high availability.

• HA Application Server

• HA Message Queue

• HA Directory Server

• HA Messaging Server

• HA Application Server EE (HADB)

• HA/Scalable Web Server

• HA Instant Messaging

• HA Calendar Server

• HA Apache Tomcat

• HA Apache

• HA DHCP

• HA DNS

• HA MySQL

• HA Sun N1 Service Provisioning

• HA NFS

• HA Oracle

• HA Samba

• HA Sun N1 Grid Engine

• HA Solaris Containers

The list of agents is not the same on SPARC and x86. For detailed information about Sun Cluster Agents, see Sun Cluster documentation at http://docs.sun.com/app/docs/prod/entsys.5.

Sun Cluster Geographic Edition 3.1 2006Q4

Sun Cluster Geographic Edition is a layered extension of Sun Cluster software. This extension protects applications from unexpected disruptions by using multiple clusters that are geographically separated and a redundant infrastructure that replicates data between these clusters. Java ES 5 is the first release to include Sun Cluster Geographic Edition as a Java ES product component.

Sun Cluster Geographic Edition includes the following subcomponents:

• Sun Cluster Geographic Edition Core

• Sun StorEdge Availability Suite

• Hitachi Truecopy Data Replication Support (SPARC only)

• EMC SRDF Data Replication

Sun Cluster Geographic Edition is not supported on Solaris x86.