4.1.1 HA cluster system
- Organization of this subsection
(1) Oracle configuration in an HA cluster system
You can improve availability of an Oracle Database (single-instance Oracle) by using it in an HA cluster system, which can perform a failover if a failure occurs.
Typically, when you operate Oracle in an HA cluster system, you construct an environment that permits execution of the same Oracle instance on both an executing node and a standby node. The configuration you use stores a single set of Oracle data (data files, configuration files, log files, etc.) on a shared disk. To control Oracle, you usually use solution products for controlling Oracle from the cluster software. For example, you use Oracle Fail Safe with Windows WSFC. For UNIX, you use products provided by various cluster software vendors.
There are also cases when the configuration or method of operating Oracle in a cluster system depends on the system.
(2) PFM - Agent for Oracle configuration in an HA cluster system
PFM - Agent for Oracle can operate in an HA cluster system and can monitor Oracle in a cluster configuration. Figure 4-1 shows a configuration for operating PFM - Agent for Oracle in an HA cluster system.
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As Figure 4-1 shows, PFM - Agent for Oracle operates in a cluster system and monitors Oracle. When a failure occurs, failover applies to PFM - Agent for Oracle at the same time it applies to Oracle, allowing PFM - Agent for Oracle to continue monitoring Oracle.
PFM - Agent for Oracle also stores definition information about the shared disk and continues operating when a failover occurs. When there are multiple Performance Management programs on a single logical host, all programs use the same shared directories.
When you monitor multiple Oracle, you can install PFM - Agent for Oracle on separate logical hosts so that each PFM - Agent for Oracle can operate and perform a failover independently.