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Tag: Active Data Guard

When does a Fast-Start Failover (FSFO) with the observer happen?

When does a Fast-Start Failover (FSFO) with the observer happen?

Often asked, well documented but a summary is always good. What are the conditions for the Observer to trigger a fast-start Failover and where do we have to place the observers? As with 19c, you might have noticed that there are less white papers published and however a pdf is easy to read, it is difficult to maintain. The world is evolving rapidly and we want to be able to provide the best and most accurate information regarding best practices…

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Redo apply is slow? Or not really?

Redo apply is slow? Or not really?

A common question that often arrives in my mailbox is that redo apply on an Active Data Guard standby database is significantly slower than on the mounted standby. A famous wise man once said: “If the primary can generate it, the standby can apply it”. I totally agree. If the primary can generate it, the standby can apply it. Larry M. Carpenter Let’s start by assuming that the redo apply best practices have been followed and the synchronous best practices…

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Automatic block media recovery to the rescue

Automatic block media recovery to the rescue

As pointed out earlier, Oracle Active Data Guard (ADG) is a lot more than just the read-only standby database. One of the technologies no other product beats us on in regards to disaster recovery is the automatic block media recovery, which is part of the Active Data Guard license. This gets automatically enabled when you open the standby database read-only with redo apply enabled. You do not need to do something specific for it, it is just there. In spite…

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AWR on ADG

AWR on ADG

Active Data Guard is a lot more than the read-only standby database. Let’s focus on this part a bit. Read-only workloads are select workloads and are just queries. Working on a read-only database where redo apply is running results in a complex mechanism of keeping data up to date and combining it with user queries. From time to time, you can’t help but question the performance of the queries or how the overall standby database is performing. What could possibly…

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DBMS_ROLLING explained

DBMS_ROLLING explained

Active Data Guard is more than just the Read-Only Standby database. Together with your Active Data Guard license comes the “Rolling Upgrade using Active Data Guard” Feature, better known as DBMS_ROLLING. If you search this blog for Transient logical standby, you can find it here. But DBMS_ROLLING is way easier. The principle remains the same: Create the guaranteed restore point Build the logminer dictionary Convert the physical standby to a logical standby Upgrade the logical standby Start the apply again…

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