Basic Software Considerations for Real Application Clusters in Oracle 12c - dummies

Basic Software Considerations for Real Application Clusters in Oracle 12c

By Chris Ruel, Michael Wessler

Before you set up your Oracle 12c Real Application Clusters (RAC), investigate the software it needs to run smoothly. Consider the following areas of software.

Operating system and Oracle 12c Real Application Clusters

Though nearly all popular OSs run an RAC installation, you need to

  • Verify that the OS is certified.

  • Make sure the right release and patchsets are confirmed as RAC certified.

  • Ensure that your Oracle version is certified with your OS configuration.

The Oracle Support website provides a matrix to help you identify certified combinations.

Furthermore, an uncertified OS may be certified later. It can be complicated at first, but getting this right to start with helps you a long way down the line.

Cluster software and Oracle 12c Real Application Clusters

Arguably, clustering software is the most important piece of software. Without clustering software, there is no cluster.

The software tracks cluster members such as databases, instances, listeners, and nodes. Lots of other cluster components run on each of the nodes and require maintenance for the clusterware to work properly. The clustering software tracks these components and facilitates internode communication and health.

Depending on your experience level with different types of clustering software, you might choose one over the other. Oracle provides clustering software in the form of Oracle Grid Infrastructure. Since Oracle 10g, Oracle Clusterware is available for almost all the major operating systems. Grid Infrastructure is the preferred software to use for clustering Oracle databases.

Prior to Oracle 11gR2, Grid Infrastructure was referred to as Oracle Clusterware.

If you go with third-party clustering software, make sure it’s certified by Oracle for RAC. Veritas and Sun Cluster are examples of certified third-party clustering software. However, make sure they’re certified for your OS.

Oracle database and Oracle 12c RAC

The Oracle database software is nothing special when it comes to RAC. You don’t need to download any special components or anything else to make an Oracle database RAC ready. RAC is built into the database software. When you go to install Oracle RDBMS on a cluster, it recognizes that a cluster exists and asks whether you would like to do a cluster install. It’s as simple as that.

Optional software and Oracle 12c RAC

You might want to use some optional pieces of software:

  • Oracle Agent: If you manage your database with Oracle Grid Control, you need to install an agent on the cluster. Like the database software, the agent recognizes that it’s being installed on a cluster and configures itself appropriately.

  • Oracle ASM: This is the preferred storage mechanism for Oracle database files in a RAC database. As of Oracle 11gR2, it is integrated with the Grid Infrastructure software stack. It is required for the Oracle Grid Infrastructure OCR and Voting disks, which are used for cluster node management and consistency. For database files, you can continue to use other shared file systems, such as raw or NFS.