Oracle Essentials: Oracle9i, Oracle8i and Oracle8, Second Edition

Complete Site Failure

Protection from the complete failure of your primary Oracle site poses significant challenges. Your company must carefully evaluate the risks to its primary site. These risks include physical and environmental problems as well as hardware risks. For example, is the data center in your area prone to floods, tornadoes, or earthquakes? Is the data center located in a facility with manufacturing activity involving hazardous or flammable chemicals? Are power failures a frequent occurrence? Even some extremely remote possibilities, such as a terrorist attack or an airplane crash into the data center, must at least be given cursory attention, since the complete destruction of corporate data that would occur in such a situation would have such a disastrous effect.

Protection from primary site failure involves monitoring of and redundancy controls for the following:

• Data center power supply

• Data center climate control facilities

• Database server redundancy

• Database redundancy

• Data redundancy

The first three items on the list are aimed at preventing the failure of the data center. Data server redundancy, through simple hardware failover or Real Application Clusters, provides protection from node failure within a data center but not from complete data center loss.

Should the data center fail completely, the last two items—database redundancy and data redundancy—provide for disaster recovery.

Emerging Technologies: Clusters Across a Distance

Some vendors are now offering clustering ...