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  • warning: Invalid argument supplied for foreach() in /www/oaktable/sites/all/modules/cck/content.module on line 1284.

Active Data Guard – what does it mean?

There are misconceptions and half-truths about that term that I see time after time again in forums, postings and comments.

Some people think that Active Data Guard is a fancy marketing term for Standby Databases in Oracle. Wrong, that is just plain Data Guard :-)

Most people think that Active Data Guard means that a Physical Standby Database can be used for queries while it is still applying redo. Not the whole truth, because that is just one featureReal-Time Query – which is included in the Active Data Guard option.

Active Data Guard is an option, coming with an extra charge. Active is supposed to indicate that you can use the standby database for production usage – it is not just waiting for the primary database to fail.

In 11g, Active Data Guard includes three features:

Data Guard transport lag in OEM 12c

I have come across this phenomenon a couple of times now so I thought it was worth writing up.

Consider a scenario where you get an alert because your standby database has an apply lag. The alert is generated by OEM and when you log in and check-it has indeed an apply lag. Even worse, the apply lag increases with every refresh of the page! I tagged this as an 11.2 problem but it’s definitely not related to that version.

Here is a screenshot of this misery:

 Lag in OEM

Now there are of course a number of possible causes:

Delete Archived Logs from Standby

This is a little surprising to me because it’s so simple – but I couldn’t find a script anywhere on oracle support or on the internet which elegantly (IMHO) cleaned up archived logs on a standby system.  (Specifically, a RAC/thread aware script.)

There are a few scripts published:

Delete Archived Logs from Standby

This is a little surprising to me because it’s so simple – but I couldn’t find a script anywhere on oracle support or on the internet which elegantly (IMHO) cleaned up archived logs on a standby system.  (Specifically, a RAC/thread aware script.)

There are a few scripts published:

DataGuard – Far Sync – part 2 - Data Guard Broker

Oracle introduced Far Sync Data Guard configuration which I described briefly in this post. Now is time for part two and using Data Guard Broker to add Far Sync instance.
Assuming that you have basic Data Guard Broker configuration ready (as described in - How to quickly build standby database and setup DataGuard configuration using Oracle 12c) adding new Far Sync instance is quite easy task.

DataGuard – Far Sync – part 2 - Data Guard Broker

Oracle introduced Far Sync Data Guard configuration which I described briefly in this post. Now is time for part two and using Data Guard Broker to add Far Sync instance.
Assuming that you have basic Data Guard Broker configuration ready (as described in - How to quickly build standby database and setup DataGuard configuration using Oracle 12c) adding new Far Sync instance is quite easy task.

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How to quickly build standby database and setup DataGuard configuration using Oracle 12c

With every release of Oracle database there are new possibilities to build a required solution (ex. standby database) faster and with fewer steps. This is not official guide but rather a mix of Oracle 12c functionality used to build DataGuard configuration using RMAN and DataGuard Broker.

Assumptions:
  • There is a database which will be used as primary.
  • New listener will be added to support standby traffic

Steps to run on primary database

Listener configuration

LISTENER_DG =

How to quickly build standby database and setup DataGuard configuration using Oracle 12c

With every release of Oracle database there are new possibilities to build a required solution (ex. standby database) faster and with fewer steps. This is not official guide but rather a mix of Oracle 12c functionality used to build DataGuard configuration using RMAN and DataGuard Broker.

Assumptions:
  • There is a database which will be used as primary.
  • New listener will be added to support standby traffic

Steps to run on primary database

Listener configuration

LISTENER_DG =