Using Application Primary/Backup Failover

Unified Assurance provides 1-1 fail-over capability within most applications. The documentation for each application can be checked to see if it supports fail-over. However, this capability is handled differently for Scheduled Jobs and Services.

For Scheduled Jobs, the broker with the backup job checks to see if the primary broker is online, and if so, the backup job will not be started. If the primary broker is offline or otherwise unreachable, the backup job will be started. This means that disabling the primary job is not enough for a backup job to be started.

For Services, the broker with the backup service will check to see if the primary service is running, and if so, the backup service will be left in a "sleeping" state. If the primary service is not running, the backup service will start processing data. This means that manually stopping the primary service will make the backup service start.

This article shows how to enable this 1-1 fail-over configuration. The same procedure is used for both Services and Scheduled Jobs.

Dependencies

• A Primary/Backup pairing will only work on servers that have been configured as a redundant pair.

• The application must be available on all servers that will be running the paired application.

Create Failover

1. Oracle recommends creating a fail-over service or job. Navigate to the Services or Jobs interface to create or copy a service or job and modify it to suit your needs. Ensure to set the correct amount of threads. Do not exceed 8 * total number of cores for total threads. The number of DB threads created will be 1/3 this number unless manually set to a different value.

   Configuration -> Broker Control -> Services

   Configuration -> Broker Control -> Jobs

   Additional configuration considerations:

   • Set Failover Type to Primary.

   • Set Status to Enabled.

2. Start the primary application.

3. Create a clone of the primary Scheduled Job/Service. Additional configuration considerations:

   • Set Server to the Unified Assurance server that will be running the backup service/job.

   • Set Failover Type to Redundant/Backup.

   • Set Primary Service/Job to the primary service or job that was created in the previous step.

   • Set Status to Enabled.

4. Start the backup application.

5. Navigate to the Failover Service States UI and validate the failover status on the Primary and Backup brokers.

   Configuration -> Broker Control -> Failover Service States

6. Navigate to the Logs UI and verify application functionality and review the application logs to see if any errors occur. The log files can be viewed in the CLI in the $A1BASEDIR/logs/ directory, or from the UI.