What a sunny day at the Oracle OpenWorld in San Francisco, temperatures over 30 degrees Celsius … don’t be jealous ;=) What should I start speaking about? Oracle Entreprise Manager Cloud Control 12c? Oracle VM or Oracle Database 12c? Well, let me summarize some of the Oracle Database 12c Data Guard new features from Joseph Meeks’s session “Oracle Data Guard Zero-Data-Loss Protection at Any Distance”.
Oracle Data Guard is a high available, data protection, disaster recovery solution. For details, please check the Oracle Data Guard Concept and Administration guide.
Business critical databases often need to be highly available and the data must be replicated untill the last transaction in case of crash.
This is achieved by the Data Guard Broker redo transportation property (LogXptMode) which is set to SYNC.
Synchronous redo transport implies a non-negligible database performance impact as the primary database waits for the acknowledgement that the transaction (commit) has also been applied on the standby.
With Oracle Database 12c, Oracle introduces a new redo transportation method which omits the acknowledgement of the transaction on the standby. This feature is called “Fast Sync” redo transport.
The cascading standby functionality has also been reviewed. But the major improvement is the ability of creating a new type of redo destination called “Far Sync Standby”.
This is especially useful for long distance Data Guard configurations; a Far Sync standby database provides the ability to failover to a terminal database with no data loss.
A “Far Sync Standby” is composed only of the standby control files, the standby redo logs and some disk space for archive logs which shall be sent to the Standby database.
Failover & Switchover operations are totally transparent as the “Far Sync Standby” cannot be used as the target. Note that it is possible to create a “Far Sync Standby” on both sides in case the database roles change.
Beside these new features the Data Guard Broker commands have been extended. One of them are in my point of view very useful: The “validate database” command checks if the database is ready for a role transition. I hope you enjoyed my posting. I will surely soon post again on these new features with more technical details.