Most frequently Asked Oracle Data Guard Interview Questions

1. What do you mean by Data Guard?
2. Can you name at least 3 top services offered by the Data Guard?
3. How do you think you would create a physical Standby in Data guard?
4. What are the services that are needed for the primary database? explain all four of them.
5. Difference Between Data Guard And Standby?
6. Go through the services which are needed on the standby database.
7. Explain briefly what is Active Data Guard?
8. Speak about some of the New Features In 11g Data Guard?
9. Explain different Steps used To Create Physical Standby Database?
10. Which are the two different Types Of Oracle Data Guard?
11. What do you mean by apply services?
12. Explain what is Redo Transport Services (RTS)?
13. Name some Advantages Of Logical Standby Database In Oracle Data Guard?

What do you mean by Data Guard?

It is software that ensures high availability, data protection from malpractices & disaster recovery for enterprise data. Data Guard provides a comprehensive set of services that will create, manage, maintain, and monitor either one or more standby databases used to enable the production of Oracle databases to survive disasters and data corruption happening. Data Guard work on maintaining these standby databases as transactionally consistent copies of the production databases. After, if the production database is found to be unavailable either because of a planned or an unplanned outage, Data Guard can easily switch any standby database to a production role, minimizing the downtime associated with its outage. Data Guard could be used along with different techniques such as traditional backup, restoration, and cluster to provide an impressive amount of data protection and data availability.

Can you name atleast 3 top services offered by the Data Guard?

Here are the top services offered by data guard:

• Redoing the transport services
• To apply for log service
• Role transitional service

How do you think you would create a physical Standby in Data guard?

Follow the below easy steps to create a physical standby in the software:

• Enable the forced logging
• Create a password file
• Configure a standby redone log
• The archiving should be enabled
• Setting up of various parameters for initialization of the primary database
• Configuring the needful settings which supports the database of both nodes.

What are the services that are needed for the primary database? explain all four of them.

Four basic services are required on the primary database as mentioned below:

The Log Writer: Used to Update online redone logs with help of collecting the information. It creates localized archived logs which can cause the transmission of the redo ones to the standby bases.

The Archive Process: online redone logs are copied for the standby bases in either remote or localized manner.

The Fetch Archive Log: Servicing of a request for archived logs present in Fetch Archive Log customers that might run on more than one standby basis. More than one server can possible run on the primary database where for each Fetch Archive Log request ,only one server could be present.

Log Network: It is used on the primary database in order to establish a connection with standby.

Difference Between Data Guard And Standby?

Data Guard: Dataguard is a mechanism or software to maintain a standby database. The data guard is set up between both primary and standby instances. Data Guard can only be accessed on Enterprise Edition.

Standby Database: It is used in providing a physically identical copy of the primary database along with on-disk database structures which are identical to the primary database on a block for block basis. Standby capability can be accessed on Standard Edition.

Go through the services which are needed on the standby database.

Four services are required on standby:

Fetch Archive Log: The archived redo files are faced to get pulled from primary sites. The transferring of the archived redo files starts on the detection of a sequence gap.

Remote File: The Primary database is used to receive either archived or standby redone logs. You could get both the archived and the standby logs together too.

Archive Process: This service is responsible for the standby redone logs that get applied by managed recovery and are archived .

Managed Recovery: The archived redo log details are then applied to the standby databank.

Explain briefly what is Active Data Guard?

Oracle Active Data Guard enables the option of read-only access to a physical standby database for queries, sorting, reporting, web-based access, etc., while simultaneously applying changes received from the production database.
Oracle Active Data Guard helps in fast incremental backing up when offloading backups to a standby database, and provides additional benefits of higher availability and disaster protection, malfunction against either planned or unplanned outages at the production site. EX: 11g Active Data Guard

Speak about some of the New Features In 11g Data Guard?

Here are some of data guard category and there enhancements Data Protection Advanced Compression Lost write protection Fast Start Fail over
Increased ROI Active Data Guard Snapshot Standby
High Availability, Faster Redo, Apply Faster failover and switchover Automatic Failover with the help of ASYNC
Manageability Mixed Windows or linux

Explain different Steps used To Create Physical Standby Database?

• Back up your primary database(DB)
• Create a standby control file.
• Transfer that full backup, init. ora and standby control file to the standby mode.
• Modify the init.ora file on standby node.
• Restore the database
• Recover Standby database(RMAN DUPLICATE DATABASE can be used as well)
• Setup FAL_CLIENT and FAL_SERVER parameters on both their sides.
• Now Put Standby database in the Managed Recover mode

Which are the two different Types Of Oracle Data Guard?

Oracle Data Guard has been classified into two types based on the way of their creation and method they use for Redo Apply.
They are as follows:
Physical standby (uses Redo Apply technology) Logical standby (uses SQL Apply Technology)

What do you mean by applying services?

Apply to redo the data on the standby database allowing it to maintain transactional synchronization along with the primary database. Redo data can be applied from either archived redo log files or simply if real-time apply is enabled, then directly from the standby redo log files, and hence doesn't require the redo data to be archived at the standby database. It only allows read-only access to the data.

Explain what is Redo Transport Services (RTS)?

It is a process that transmits redo from a primary database to a standby database.
RDS control the automated transferring of redo data from one database destination to one or more destinations. RDS also resolves any gaps in the archived redo log files that arrived due to a network failure.

Name some Advantages Of Logical Standby Database In Oracle Data Guard?

• Better usage of resource
• Data Protection
• High Availability
• Disaster Recovery