OCM 12c Preparation

Oracle Certified Master is one of the prestigious exam in database world. Most of the Oracle DBA have a dream to be OCM certified. This certification will distinguish you from others in Market.

Prerequisites to be OCM Certified: Details

Oracle 12c OCM exam is based on Oracle Database 12c Release 1 and includes the use of Oracle Real Application Clusters (Oracle RAC). The operating system is Oracle Linux Server Release 6.5.

Exam Environment


  • Oracle Linux Release 6.5 64 bit
  • Mozilla Browser, Text (emacs, gedit) and vi editors
  • Shell environment: bash, csh
  • Use either CLI or GUI environment and tools when available
  • Oracle Database 12c Enterprise Edition Release  64 bit
  • Oracle Grid Infrastructure 12Release 1 (
  • Oracle Enterprise Manager Cloud Control 12c Rel 4
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Setup Password less connection using SSH for User Equivalence on Linux

Setup SSH (Key-Based Authentication)

Password less connectivity is required for RAC setup. Sometimes need to send files from one server to another using script with scheduler job. For this kind of tasks, password less connectivity is required. Password less connectivity can setup one direction (from server A -> B) or both directions (From Server A -> Server B or vs).

Execute following command on both Nodes:

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Add a New Disk to an Existing Linux Server

In this article describes how to add a file system on exiting Linux OS. As OS is running on VM, First will show how to add a disk on VM then Create a Filesystem on OS Level.

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Step by Step of Installation Oracle Enterprise Manager (OEM) 13c ( on RAC

Oracle Enterprise Manage (OEM) is a great tools to monitor and manage all kind of oracle software including Oracle Databases and Server.

  • Create Database
  • Install OEM Software
  • Install Agent
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Oracle Database Migrate Using Mixed Oracle Version

We will discuss how to use mixed version of Data Guard to upgrade upper version with minimal downtime. DBA should not take 1% risk for most critical database in a company during migration or upgradation and must have to plan to rollback option for worse case.

Let say you are working in a big company and you need to upgrade a most critical database in company and you have only 6-10 hours down time to upgrade or migrate the database. You have to consider the rollback option on any state of migration processes for any kind of issues.

In this case, most appropriate way to upgrade or migrate using GoldenGate. But management may not agree to use GoldenGate because for budget shortage. So you have use this approach to minimized the downtime and risk.

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Create Duplicate Or Refresh the Database Using RMAN Backup on RAC

Create duplicate database or refresh the database from production backup for testing purpose is one of the regular activities for DBA. I will discuss and show how to create duplicate database using RMAN backup.

Scenario: Production database running on two nodes RAC and need to refresh the database for testing purpose on testing environment.

  • Production DB Name: orclp
  • Production Nodes: racprod1, racprod2
  • QA DB Name: orclq
  • Test DB Nodes: ractest1, ractest2
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Multiple Tables Record Count by a Single Query

Sometimes DBA need to verify or compare multiple tables record count. It is really time consuming to compare one by one table count. So, by using this query, you will able to get record count report for multiple tables in Oracle.

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Move Objects From One Tablespace to Another Tablespace in Oracle

Sometimes need to move objects from one Tablespace to another in Oracle Databases. We can do this multiple ways.

  • Move a single object from Multiple Tablespace (one TBS for DATA, another for Index and LOB) to different set of Tablespace
  • Move all objects of a schema from Multiple Tablespace (one TBS for DATA, another for Index and LOB) to different set of Tablespace
  • Move all objects from one Tablespace to another Tablespace
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Tips to Avoid Mistake and Be a Safer DBA

There is around 33% disaster occurs on database world for user error/mistake.

If you follow couple of rules, you will able to overcome lots of possible mistake.

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Installing Oracle Client In Silent Mode on Linux

In this article I will show how to install Oracle Client 11g, 12c, 18c and 19c in Silent Mode on Linux.

  • Download Software.
  • Prepare response File.
  • Installation
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