Database Reference
In-Depth Information
how to set the CPU count to manage CPU resources for those pre-11g R2 Database instances. The related whitepaper
on the Database consolidation topic is Oracle whitepaper “Best Practices for Database Consolidation in Private
Clouds,” which can be found at the following URL:
www.oracle.com/technetwork/database/focus-areas/database-
As one of the most important new features introduced in Oracle 12c, the pluggable database provides a better
solution to consolidate multiple database services. In Chapter 4, we explain in detail how the pluggable database
feature works in the Oracle RAC 12c environment and how to implement the multitenancy of database services by
consolidating multiple pluggable databases into a single container database running on Oracle RAC 12c.
Considerations for Deploying RAC
As we have shown in this chapter, RAC embodies a great technology solution for achieving HA and scalability of Oracle
database services. However, this solution itself has a complex hardware and software technology stack. Before an IT
organization decides to adapt Oracle RAC technology for its database architecture, it should be aware of the advantages
and potential disadvantages of the Oracle RAC technology, and its implications for the organization's business
goals. This will help to justify the adoption of Oracle RAC for the business. The next section highlights some related
considerations that will help you decide whether or not Oracle RAC should be used as the database architecture.
Cost of Ownership
One of the possible reasons that IT departments are looking at Oracle RAC is to reduce the cost of ownership of the
database infrastructure. This cost saving is relative, depending on what you are comparing. The cost of Oracle RAC
implementation includes three parts: hardware infrastructure cost, Oracle software cost, and management cost.
The hardware stack consists of multiple servers, redundant networks, and shared storage. The software cost mainly
includes Oracle RAC license and the Oracle Database license. For Oracle Database Enterprise Edtion, the Oracle RAC
license is separate from Oracle Database license, while for Oracle Database standard edition, the Oracle Database
license already includes the Oracle RAC license which you don't have to pay for separately.
One of the limitations of Oracle Standard Edition is that the total number of CPU sockets of all the servers in the
cluster can not go beyond 4. A
CPU socket
is a connection that allows a computer processor to be connected to a
motherboard. A CPU socket can have multilple CPU cores. For example, a Dell R820 server has four CPU sockets while
a Dell R720 server has two sockets. Since each socket can have 8 cores, an R820 server can have up to 4 * 8 = 32
CPU cores, and a Dell R720 server can have up to 16 CPU cores. Using Oracle Standard Edition with a maximum
capacity of 4 CPU sockets, you can make a two-node Oracle RAC cluster with Dell R720 servers, but only a one-node
cluster with a Dell R820 server. For Oracle Enterprise Edition, the RAC license can be based on the total number
of processors. This is based on the total cores of the servers in the cluster. For example, for a two-node Oracle RAC
configuration using Dell R720s with 8 core CPU sockets, the total number of the CPU cores can be 2 * 2 * 8 = 32.
Management staff cost is related to the cost of training and attracting individuals with the skills needed (system
admins, network admins, and DBAs) to manage it. The hardware and software costs include the initial purchase cost
as well as the ongoing support cost. Although this cost is higher than a simple database solution like a single-node MS
SQL server, the RAC solution is cheaper than typical complex mission-critical databases running on big SMP servers,
as Oracle RAC is mainly implemented on Linux and industry-standard low-cost commodity hardware. In the last
decade, these industry-standard servers running Linux have become much cheaper, and offer a powerful and reliable
solution widely accepted for enterprise systems.
Another cost-saving factor is that Oracle RAC can be implemented as a shared resource pool to consolidate many
databases. This can significantly reduce the costs of hardware, software, and management by reducing the number of
systems. In the Oracle E-Business database consolidation example mentioned in the last section, 100 databases were
consolidated onto a 16-node RAC. The number of database servers was reduced from 100 or more to 16. The reduction led
to huge savings in hardware, software, and management. As already mentioned, long-term operating costs are also cut by
reducing the need for support, maintenance, and even powering and cooling 100 systems in a data center for the entire life
cycle of the environment. For full details of this example, refer to my technical presentation at Oracle OpenWorld:
