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I want to open the discussion about the Data Guard Configuration.

A Data Guard configuration consists of one production database and up to nine standby databases. A standby database can be either a physical standby database or a logical standby database.

As the DBA, which one is the best choice to use? Physical or Logical standby database?

Sarith

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3 Answers 3

up vote 4 down vote accepted

Physical Standby is typically DRP-oriented. Its main advantages are:

  • List item
  • easier to setup
  • support every data type
  • faster apply

In 11g, you can easily utilize it for testing (snapshot standby). Also, if you license Active Data Guard option, you can use it for near real time reporting (under some limitations - the standby is readonly, but some workarounds are available - see Apendix B in the best practices paper). Active Data Guard also allows you to perform fast incremental backups on the DR site instead of the primary

Logical Standby was typically used to enable reporting on a standby. Its main advantages are:

  • Standby is open for reporting without extra license.
  • you can add indexes / MV specific for the standby
  • you can add your own app shemas and your own updatable tables in the standby

So, for pure DRP, use physical. If you need read only access, decide based on these features. For example, check data type support, see if you need the faster apply performance, see if you are willing to license Active Data Guard (and upgrade to 11g if you are not there) etc.

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+1 for a good summary of the two types. Note if you're using 10g you can't do much with the physical standby without shutting it down and re-opening it in readonly mode, during which time it is not staying up to date with primary. –  DCookie Jun 25 '09 at 15:32

Logical Standby was typically used to enable reporting on a standby. Its main advantages are:

* Standby is open for reporting without extra license.

According to the latest pricing policy a license is required also for Logical Standby. link text

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It can help you.

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