Configuring Service Groups to Automate the RAC Environment

VCS can be configured to automate the Oracle RAC environment as well. Depending on installed configuration and level of control desired, the implementer can create service groups to bring up the ORACLE_HOME and listener, mount database storage, as well as start and stop Oracle database instances.

There are a number of configuration choices that affect the overall cluster design. These choices will be discussed briefly in the next several paragraphs.

Is Oracle Installed on Shared or Local Storage?

You can install the Oracle binary on shared storage, that is, in a cluster file system, where it is shared by cluster systems, or you can install it on each system in a local file system.

When the Oracle binaries are installed locally, the file system for ORACLE_HOME may be mounted as part of the normal boot process. If this is the case, no VCS involvement is necessary.

When Oracle binaries are installed on a cluster file system, CVM and CFS need to be online before ORACLE_HOME is mounted. Placing the ORACLE_HOME resource under VCS control allows proper dependency relationships to be built for proper start up sequencing. The CFSMount agent and CVMVolDg agents are used for control.

Is SRVM Located in ORACLE_HOME or a Separate Disk Group?

The SRVM component must be installed on shared storage if the user wishes to use any of the Oracle supplied tools to manage the database. The SRVM configuration files can be placed on either a cluster file system or a shared raw volume. The preferred method is to configure SRVM as a directory on the shared ORACLE_HOME. Alternate locations for the SRVM component include a shared volume or shared file system in a separate disk group.

Does the Listener Use a Virtual IP Address?

The Listener may be configured to use a virtual IP address or host IP address.

Applications to Address RAC Databases on the Same Server?

If the user intends to create service groups to manage applications accessing the RAC instances in the cluster, special consideration may have to be given to service group layout.

Understanding VCS Service Group Dependency Capabilities and Limitations

VCS supports dependencies between service groups. For example, a service group containing a RAC instance may require another service group containing the Oracle binaries and listener. This group may in turn require the CVM group be online to provide CVM and CFS support.

The following illustration shows various supported service group configurations. The circles represent parallel service groups running on each RAC node. For example, the left most configuration has the Oracle binaries and network component in a service group that depends on the CVM group for necessary daemon support for CVM and CFS. The next configuration shows a database added to the service group. The two example configurations to the right show better arrangements, because they allow for multiple service groups containing individual databases to be independently managed.

Supported Service Group Configurations

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VCS supports a maximum of three dependency levels deep. It also supports only one child dependency group; that is, one service group cannot depend upon two others. The following diagram shows unsupported service group dependency configurations.

Service Group Configurations Not Supported by VCS

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For users wishing to create additional service groups to manage applications and stay within the dependency limitations of VCS, VERITAS recommends moving all cluster infrastructure components, including ORACLE_HOME and the listener to the CVM service group.

Supported Configuration: Infrastructure Components in the CVM Service Group

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