Chapter 15. Using High-Availability Options

In This Chapter

  • Using Real Application Clusters (RACs)

  • Understanding Data Guard

A high-availability architecture combines hardware and software solutions to help reduce the impact of outages during planned and unplanned downtime. Your data's availability is of utmost importance. However, the level of availability varies by business. Some can deal with a little downtime here and there with minor business interruptions. A minute of downtime for others can cost tens of thousands of dollars. Luckily, Oracle helps harden against the forces out there that want to make your database unavailable.


Implementing a high-availability architecture may not be cost effective for everyone. It can be expensive in terms of hardware and software licenses. However, if downtime costs you thousands of dollars in short intervals, look at some of Oracle's high-availability options.

This chapter is about a couple of Oracle features that you can configure for high availability. Each feature has its strengths and weaknesses. You sometimes can combine features to get the best result. And because licensing Oracle options seems to change constantly and varies from site to site and version to version, we're deferring any questions about the licensing of these features to your friendly Oracle sales rep.

Lastly, entire books and weeklong classes deal with these technologies. We give an overview within this chapter. Unfortunately, we can't prepare you for an enterprise installation ...

Get Oracle® 11g For Dummies® now with the O’Reilly learning platform.

O’Reilly members experience live online training, plus books, videos, and digital content from nearly 200 publishers.