 |
|
|
Architecture and ComponentsInstallation and configuration of the RAC system on multiple nodes involves many steps. Unlike a standalone Oracle database installation, a RAC installation is highly integrated with the cluster environment at the server level. The RAC database software installation process is cluster aware; in other words, the Oracle software detects the existence of the cluster infrastructure as it is installed. From the point of view of the installer, the main architecture of the RAC environment includes [See Fig 6.1] the following:
The nodes or servers are the main platforms on which the Oracle RAC database is installed. The cluster nodes range from a high end powerful Sun Fire 15K to a low end Linux server. They can also range from a mainframe grade IBM zSeries server to the emerging blade-server technologies such as IBM BladeCenter or Egenera. We need to first install the appropriate operating system on the nodes. It is also important to choose the appropriate number of nodes while setting up the node-operating environment. Fig 6.1 shows the overall components involved in a typical installation and configuration. Fig 6.1 Overall Architecture (installation view) The private interconnect is the physical construct that allows the inter-node communication. It can be a simple crossover cable with UDP or it can be a proprietary interconnect with specialized proprietary communications protocol. If we are planning to set up more than 2-nodes, a switch is usually needed. This provides the maximum performance for RAC, which relies on inter-process communication between the instances for cache-fusion implementation. Creating clusters involves installing the cluster software on all nodes in the proposed cluster, as well as checking the configuration. We need to perform the necessary tests to verify the validity of the cluster. At the same time, the necessary software that controls the private interconnect is also installed and configured. The storage system provides an external common disk system accessible by all nodes of the cluster. The connection from the nodes to the disk sub-system is usually through a fiber switch or a SCSI connection. Once the storage volumes are presented to the hosts in the cluster, usually with the help of the logical volume manager, one can create volumes of suitable size for use in the RAC database. The clustered servers or hosts need to have public network connectivity so that client machines in the network can access the resources on the RAC system. Oracle9i Enterprise Edition contains the RAC installation software (a valid license should be obtained to use this option). The Oracle Configuration assistant’s tools are user-friendly with a graphical interface. Typically, the tools start automatically after installation depending on the selection made when starting the installer. We can also manually start the configuration assistant as a standalone tool(s). They include:
For more information, see the book Oracle 11g Grid and Real Application Clusters - 30% off if you buy it directly from Rampant TechPress . Written by top Oracle experts, this RAC book has a complete online code depot with ready to use RAC scripts.
|
|
|
