Database Reference
In-Depth Information
Summary
Well thought-through naming conventions make the life of the database administrator a lot easier. With Data Guard
a new dimension is added to the scope of the naming convention. Database instances in a Data Guard environment
should probably not be named after their role, especially not in a consolidated environment. A location could be a
good name, otherwise users might get confused when the database STANDBY1 is in the primary role.
Standby databases are easily created using the RMAN duplicate database command. You read about the two
possible cases for database duplication: to file system or to ASM/OMF based storage.
Finally you read more about configuration a Data Guard environment. The large number of configuration options
and choices are nicely hidden from view when using the Data Guard Broker interface. In addition to the Broker
command line interface you can use Enterprise Manager. OEM will pick up any existing Broker configuration and
allow you to manage the environment.
Recent versions of Enterprise Manager have had great support for Data Guard, and centrally managed monitoring
templates make it easy to alert the database administrator on shift when there are problems. The Enterprise Manager
Data Guard pages offer a great view of the various performance metrics in the Data Guard configuration, most notably
the transport and delay lags. If you wanted you could even use Enterprise Manager to monitor and maintain Data Guard
configurations, including the initial creation of a standby database.
Less experienced DBAs find role transitions intimidating and scary, but they need not be. Instead, practice,
documentation, and training will make a switchover a standard procedure much like opening and closing a database.
The “practice” aspect cannot be overrated in this context. If a failover situation occurs for some reason stress levels are
guaranteed to rise. Good documentation and confidence will help getting the system up and running on the disaster
recovery site more easily.
The Broker command line interface again is a great way of simplifying the role transitions, and the bet is that
it will take longer to get approval for the role transition than it takes to carry it out. Despite the fact that the Oracle
database is highly resilient to problems during a role transition one should not forget to regularly test if applications
continue to function after a role reversal. Strict coding standards should prevent hard coded connection strings from
entering production applications, but time pressure can lead to cutting corners, reinforcing the need to perform
regular tests.
 
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