Oracle 11g R1 / R2 Real Application Clusters Handbook: Design, implement and support complex Oracle 11g RAC environments for real world deployments

We will begin our discussion of the RAC architecture for Oracle 11g at the macro level from 50,000 feet, with an example three-node Oracle 11g RAC environment as shown in the following diagram:

This diagram illustrates a fully redundant Oracle 11g RAC architecture in terms of hardware, network, storage, and database layout and configurations. Later in the chapter, we will in turn explain each of these key components and how they function within the grand scheme of an Oracle RAC environment. We also will provide you with guidance on how to best choose the right components for your Oracle RAC environment. As you can see, Oracle RAC is a complex mix of system, network, and database technologies. This provides the ability to scale up or out for large mission-critical information systems to support either OLTP (Online Transaction Processing), DSS (Decision Support Systems), and Data Warehouse, or ERP environments such as Oracle 11i/R12 EBS and PeopleSoft or SAP. The...

As database professionals, you will be tasked with finding the best hardware solution when implementing a new RAC environment for Oracle 11g. Cost, performance, and support are key factors to take into account when designing the hardware architecture for RAC. Many considerations need to be planned out for the correct hardware selection for a new or future RAC implementation. We advise that you hold meetings not only among the database team but also with the system, network, and storage administration teams to perform the initial planning of your hardware, storage, and network architecture needed for 11g RAC environments. There is no one-size-fits-all approach when it comes to laying the foundation for 11g RAC. Vendors also provide resources for sizing and validated configurations that are supported with all of the layers of the Oracle 11g RAC technology stack. The majority of long term RAC architectural and design issues are due to a lack of using...

The Oracle 11g RAC technology places a lot of responsibility on the network layer within the data center; it requires a high performing public as well as private network to deliver the optimal rate of scalability, performance, and availability. Because the data within an RAC environment must pass across the interconnect network interfaces, you will need to size and tune the network interfaces accordingly or suffer from performance issues within your 11g RAC environments.

Oracle 11g RAC cluster nodes share the same storage array that contains the 11g RAC database. As such, the sizing and choice of the storage is of critical importance for design and implementation of your RAC configuration. By understanding disk I/O with respect to how RAC uses storage disks, you will be able to optimize your design so that performance is optimized from the ground up, rather than reacting to a poor design, which will be more difficult to resolve after.

As the database architect responsible for designing the environment for Oracle RAC, you should understand that storage layout is one of the most important considerations to make for the best performance and availability factors within the system architecture. If you use the wrong storage protocol for a large RAC ecosystem, then performance issues will occur within your overall data center environment. Therefore, it is critical to have a solid understanding of storage protocols such as Small Computer System Interface (SCSI), Fibre Channel (FC), and Internet Small Computer System Interface (ISCSI) that may impact your Oracle RAC setup and configuration.

You will need to evaluate and implement these as part of your RAC configuration for Oracle 11g. The chapter will discuss the merits and weaknesses of these storage protocols for you to be able to choose the correct configuration for RAC based on your business requirements. There are additional storage protocols that...

In addition to the many hardware, network, and storage components that drive the foundation of Oracle 11g RAC, we have the complex software called Clusterware that lies at the heart of the Oracle RAC architecture. Oracle 11g RAC consists of these physical devices along with the Clusterware and Automatic Storage Management (ASM) software. ASM provides the mechanism for managing storage within RAC environments and uses both a special type of instance called an ASM instance as well as special disk volume management in the form of ASM disks and ASM diskgroups. Clusterware refers to the Oracle software layer that performs the operational tasks within the Oracle-clustered environment for RAC. In summary, the Clusterware consists of the following components for Oracle 11g RAC:

In addition to the Oracle 11g Clusterware...

There are many new features in Oracle 11g RAC that are introduced with ASM enhancements. Many of these involve ASM configuration.

With Oracle 11g, there are now two new Disk Group compatibility attributes—compatible.asm and compatible.rdbms. These disk group compatibility attributes determine the minimum version of ASM and database instances that can connect to an Oracle 11g ASM disk group. By advancing these disk group compatibility settings, you can use the new ASM features that are available in the latest release. If you decide to advance these attributes from 10.1 to 11.1, you will enable the following key features that are new to Oracle 11g ASM:

The software version of ASM determines the default compatibility of newly created disk groups. You can override the disk group compatibility default setting when you create disk groups with the CREATE DISKGROUP SQL statement.

The ALTER DISKGROUP SQL statement can update the compatibility settings for existing disk groups.

The compatibility settings for a disk...

This chapter has provided you with a comprehensive discussion of 11g RAC architecture, focusing on the following topics:

Because understanding the initial design is important for a successful deployment of Oracle 11g RAC, the chapter focused on all aspects of the system architecture that must be accounted for to ensure success. This included an in-depth discussion of hardware server configurations, network design, and RAID configurations, as well as storage protocols for managing the disk I/O subsystem. Based on the constraints of your business operations and performance needs, you can now decide what system configurations will best suit your deployment of Oracle 11g RAC from all of these key perspectives. The chapter then moved on to discuss the summary of RAC components and new features that are important to be aware of while working with 11g R1 and 11gR2 RAC, and with ASM.

The...