What is Data Guard failover?

Failover is a one way process where your primary database goes down due to some reasons and to get back the production live without any loss, you convert your existing Physical Standby database to start behaving as Primary database.

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What is fail over and switch over?

Answer: In general, a failover is a production emergency, where the primary database has failed and you need to failover to the standby database. Conversely, a switchover is a planned switch from a standby back to the primary database, a non-emergency operation.

What is the meaning of Data Guard?

Data Guard provides a comprehensive set of services that create, maintain, manage, and monitor one or more standby databases to enable production Oracle databases to survive disasters and data corruptions. Data Guard maintains these standby databases as transactionally consistent copies of the production database.

What is switch over in database?

A switchover is a role reversal between the primary database and one of its standby databases. A switchover guarantees no data loss. This is typically done for planned maintenance of the primary system.

How do you failover in Oracle Data Guard?

On the Oracle Data Guard Overview page in Cloud Control, select the standby database that you want to change to the primary role and click Failover. Then, on the Failover Confirmation page, click Yes to invoke the default Complete failover option.

What is the difference between failover and failback?

The failover operation is the process of switching production to a backup facility (normally your recovery site). A failback operation is the process of returning production to its original location after a disaster or a scheduled maintenance period.

What are the types of Data Guard?

There are 3 types of standby setup:

Physical standby.
Logical standby.
Snapshot standby.

What causes a failover?

The following events can cause failover in a high availability configuration: If the secondary node does not receive a heartbeat packet from the primary node for a period of time that exceeds the dead interval set on the secondary.

What is SQL Server failover?

SQL Server failover clusters are made of group of servers that run cluster enabled applications in a special way to minimize downtime. A failover is a process that happens if one node crashes, or becomes unavailable and the other one takes over and restarts the application automatically without human intervention.

What is a failover in Oracle database?

A failover is a role transition in which one of the standby databases is transitioned to the primary role after the primary database (all instances in the case of an Oracle RAC database) fails or has become unreachable.

How do you do a failover?

In Object Explorer, connect to a server instance that hosts a secondary replica of the availability group that needs to be failed over. Expand the server tree. Expand the Always On High Availability node and the Availability Groups node. Right-click the availability group to be failed over, and select Failover.

How do you failover a server?

From the OS of any of the nodes:

Click Start > Windows Administrative tools > Failover Cluster Manager to launch the Failover Cluster Manager.
Click Create Cluster.
Click Next.
Enter the server names that you want to add to the cluster.
Click Add.
Click Next.
Select Yes to allow verification of the cluster services.

What is the difference between Data Guard and Active Data Guard?

The main difference between Oracle Data Guard and Active Data Guard is that Oracle Data Guard is an extension to the Oracle RDBMS that provides data availability and protection while Active Data Guard is an extension of Oracle Data Guard that improves the production database performance for critical transactions.

How do you set up a data Guard?

Use the following configuration best practices for Data Guard:

Use Oracle Data Guard Broker with Oracle Data Guard.
Use Recovery Manager to Create Standby Databases.
Use Flashback Database for Reinstatement After Failover.
Use FORCE LOGGING Mode.
Use a Simple, Robust Archiving Strategy and Configuration.

What is the difference between Oracle Data Guard and Active data Guard?

What are failover systems?

Failover is the ability to seamlessly and automatically switch to a reliable backup system. Either redundancy or moving into a standby operational mode when a primary system component fails should achieve failover and reduce or eliminate negative user impact.

Why does failover happen?

Failover occurs when users cannot access the server that contains the database they want or they cannot access the database itself. When a user tries to open a database that is not available, the Cluster Manager looks in the Cluster Database Directory for a replica of that database.

Does Oracle Data Guard automatically start after a switchover?

If the service has been configured to start automatically ( -policy AUTOMATIC ), then the service will automatically start only after a database role change. In an Oracle Data Guard configuration, the SRVCTL -startoption for a standby database is always set to OPEN after a switchover.

What is Oracle Data Guard and how does it work?

Oracle Data Guard helps you change the role of databases between primary and standby using either a switchover or failover operation. A switchover is a role reversal between the primary database and one of its standby databases. A switchover guarantees no data loss and is typically done for planned maintenance of the primary system.

What is an observer in a Data Guard?

An observer process is integrated in the DGMGRL client-side component of the broker and typically runs on a different computer from the primary or standby databases and from the computer where you manage the broker configuration. There can be up to three observers for a single Data Guard configuration.

Can two observers on the same data guard broker have the same name?

No two observers on the same Data Guard Broker configuration can have the same name. If no name is specified for the observer then a default observer name, the host name of machine where the START OBSERVER command is issued, is used. An observer name is case-insensitive. The string “NONAME” cannot be used as an observer name.