What is Cluster and How can we find if a Database is running on Cluster

November 4, 2020

What is Cluster and How can we find if a Database is running on Cluster

Oracle Real Application Cluster provides its users to run a single database into multiple servers. These multiple servers act as a single system. It provides fast recovery at the time of any site failure. To avoid the outage and provide High Availability, redundancy for its users in case of instances/databases crash. Hence Users connected to these databases will be sharing shared storage. The benefit of having multiple instances access a single database is just to avoid the server from failure for a single point. Compare to single instances, RAC is a bit costlier. As it’s having a scalable environment to support Critical Applications of any Organization. If you’re planning to deploy RAC then without code changes also it can work.

The below-mentioned query we can use to check if the database is running on Single Instance or RAC ( Real Application Cluster).

To check if the Database is configured with Cluster. Click here for sample output.

SET LINES 200
SET PAGES 200
COL NAME FORMAT A19
COL VALUE FORMAT A19
SELECT NAME, VALUE FROM V$PARAMETER WHERE NAME='cluster_database';
prompt$$$$$$$**Welcome to DBsGuru!**Share Learn Grow**$$$$$$$

If the result is coming as ‘TRUE‘ then the Database has enabled with cluster services running as one or more than one Instance and in-case if the result is coming out as ‘FALSE‘ then it’s a standalone Instance Database.

To check active DB status with RAC”s instance name along with the connected server. Click here for sample output.

SET LINES 200
SET PAGES 200
COL INST_NAME FORMAT A40
SELECT * FROM GV$ACTIVE_INSTANCES;
prompt$$$$$$$**Welcome to DBsGuru!**Share Learn Grow**$$$$$$$

This document is only for learning purpose and always validate in the LAB environment first before applying in the LIVE environment.

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