Red Hat Enterprise Linux – High Availability (HA) on Cluster Suite Using Red Hat High Availability
- Oracle Enterprise Edition has a separately priced option called Real Application Clusters(RAC) and this does provide for shared access, or multi-instance, shared operation.
- Real Application Cluster is much more costly for Oracle Enterprise Databases.
- Red Hat Cluster Suite Oracle RAC is certified only for use with GFS shared volumes.
- Oracle RAC supports more than eight nodes and most customer deployments are typically four to eight nodes. The mechanics of a multi-node RAC installation can be demonstrated with the same two-node cluster that can be used for Enterprise Edition HA. This provides an equivalent configuration for comparison and to determine which option is best for your requirements.
- Achieve the same high availability on two-node cluster as compared with Oracle RAC.
Sample two-node cluster
The below figure shows a generalized overview of the two-node cluster configuration. In this configuration, there are two nodes, each with a fencing agent and each connected to shared storage. There is also an application tier network that accesses the nodes.
Oracle High Availability Failover Domain on Cluster Suite
When Node 2 detects a failure occurs in Node 1, the fence agent 2 will send fence command to node 1. All the database and listener processes will stop in node 1. Once Node 2 confirms that Node 1 is disconnected from the shared storage, Node 2 start the oracle database locally using the virtual IP1. Similar case when Node 2 fail: