Oracle Database Standard Edition High Availability

Oracle announced a High Availability option for use with Oracle Database Standard Edition 2 (SE2) beginning with version 19c.  So far, as of Release Update 19.7, Oracle has included these operating systems: Linux, Solaris, and Microsoft Windows.  More are planned in the future.

Oracle customers can still use the maximum supported 16 CPU threads per instance during normal operations as well as Failover.

Rather than using RAC as before, RACless version 19 SE2 customers can use free of charge storage management and high availability capabilities included with Oracle Grid Infrastructure.  Oracle claims this is one of the fastest failover solutions available*

Oracle does intend that this configuration could be true failover, without additional licensing, if it adheres to Oracle’s definition of Failover.  As a reminder, Oracle currently defines Failover as:

“the right to run the licensed program(s) [here the Standard Edition High Availability database] on an unlicensed spare computer in a failover environment for up to a total of ten separate days in any given calendar year. This right only applies when a number of machines are arranged in a cluster and share one disk array, which is the case for Standard Edition High Availability databases by default.

In addition, SEHA databases are subject to all licensing regulations that generally apply to a Standard Edition 2 (SE2) single-instance Oracle Database. Note that SEHA databases are not subject to a per-cluster socket limitation, but need to adhere to the per-server socket limitation that applies to any Standard Edition 2 Oracle Database.”

(Michalewicz, 2020, https://blogs.oracle.com/maa/standard-edition-high-availability-officially-released)

As Oracle posted on their blog, the licensing benefit of this failover configuration for Standard Edition 2 is the second server’s database instance(s) will not require additional licensing.  That would be an improvement over SE or SE2 with RAC included because with that configuration, you licensed the second database.

What about the cost of Oracle Clusterware?  Oracle provides this information in their Oracle Database: Database Licensing Information User Manual:

Oracle Clusterware may be used to protect any application (restarting or failing over the application in the event of a failure) on any server, free of charge.  Oracle will provide support for Clusterware only is the server is running an Oracle product, which may include Oracle Linux or Oracle Solaris, that is also under Oracle support.

Oracle has already issued the suggested architecture, including sample diagrams.   Oracle’s additional information on this configuration:

Oracle Clusterware requires a virtual IP address for each node in the cluster. With Oracle Clusterware you also define an application virtual IP address so users can access the application independently of the node in the cluster where the application is running. You can define multiple application VIPs, with generally one application VIP defined for each application running. The application VIP is tied to the application by making it dependent on the application resource defined by Cluster Ready Services (CRS)

(Oracle, 2020, https://docs.oracle.com/cd/B28359_01/server.111/b28281/architectures.htm#g1012375)

Figure 1. Oracle Database with Oracle Clusterware after Cold Failover

Figure Source: [Oracle] Database High Availability Overview, High Availability Architectures and Solutions. Copyright Oracle, 2020. Located at https://docs.oracle.com/cd/B28359_01/server.111/b28281/architectures.htm#g1012375

Please note, this configuration may not provide the level of redundancy you desire for a robust Disaster Recovery solution, since the failover server and database instance occupy a node in the same cluster as the primary.

If you’d like more information on Oracle Clusterware for Oracle Database 19c, Oracle’s white paper is located at

https://www.oracle.com//technetwork/database/database-technologies/clusterware/overview/oracle-clusterware-5296165.pdf

 

* Fast failover time referenced by Markus Michalewicz on Oracle’s blog post “Standard Edition 2 – We Heard You! Announcing: Standard Edition High Availability”, March 2, 2020 at https://blogs.oracle.com/maa/standard-edition-2-announcing-standard-edition-high-availability

 

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