Setup and configuration

The SunPlex system achieves high availability through a combination of hardware and software. The redundant cluster interconnects storage and public networks to protect against single points of failure. The cluster software continuously monitors the health of member nodes and prevents failing nodes from participating in the cluster, protecting against data corruption. Also, the cluster monitors services and their dependent system resources, and fails over or restarts services in case of failures. There are several steps to configure a Sun Cluster for WebSphere:

1. Connect and configure the shared disk subsystem:

Database data and log files are stored in a mirrored or RAID shared disk array that can be connected physically to two nodes (multihost disk). When one node fails, the other node can access the same data and log files.

You can configure the shared disk using either Sun Cluster Solstice Disksuite or VERITAS Cluster Volume Manager.

2. Install and configure Sun Cluster data service software:

Install the Sun Cluster software. Sun Cluster will use the su command when it starts or stops the database server. In order to avoid the impact of failed network information name service during failure of the public network on the cluster node, modify the /etc/nsswitch.conf file on each node where the logical host will run so that group lookups are directed to files first.

3. Install and configure DB2 and Oracle:

You can select to install DB2 or Oracle binaries either on the local disks of each node or on the multihost shared disks. Placing database binaries on the multihost disk eases administration, since there is only one copy to administer. However, it sacrifices redundancy and therefore availability in some failures. Placing database binaries on the local disk of the physical host increases redundancy and therefore availability. However, placing the binaries on the local disk increases the administrative overhead, since manage multiple copies of the files. If you select to install on the local disks, the version of the database must be the same.

When first installing DB2 or Oracle, select the Install only option. This is necessary because database initialization and configuration files must be modified to reflect the logical hosts as the location for the database. Install DB2 or Oracle as usual (see the corresponding DB2 or Oracle product manuals).

4. Make DB2 and Oracle database cluster-ready for failover:

Start the Sun Cluster and take ownership of the disk group using:

scadmin startcluster

Make sure that the multihost disks have been configured properly. Create the DB2 instance or Oracle database. After that, make it cluster-ready. Register the database service using:

hareg -s -r Oracle -h waslh

Activate the database service using:

hareg -y Oracle

And finally set Sun Cluster to monitor the database instance and bring the database into service.

WebSphere must use the logical host name (not the physical host name) to access the database. When the database server fails from the primary host to the secondary host, you do not need to change the WebSphere database connection string, since the logical host name is the same before and after a failover.

5. Verify the cluster configuration:

You can perform a verification using haswitch. You can also check the status using hastat.

  Prev | Home | Next

 

WebSphere is a trademark of the IBM Corporation in the United States, other countries, or both.

 

IBM is a trademark of the IBM Corporation in the United States, other countries, or both.