Data Guard

Background

The purpose of Oracle Data Guard is to ensure high availability, data protection, and disaster recovery for Oracle databases by maintaining standby databases that can quickly take over if the primary database becomes unavailable.

In Oracle 19c Data Guard, a SWITCHOVER and a FAILOVER are both operations that change the roles of primary and standby databases, but they serve different purposes and are used in different scenarios:

Switchover

• A planned operation.
• No data loss.
• Both primary and standby databases are synchronized and available.
• Suitable for maintenance, upgrades, or when you know in advance that the primary database will be unavailable.

Failover

• An unplanned operation.
• May result in some data loss, depending on the lag between the primary and standby databases.
• Used in emergency situations where the primary database is unexpectedly unavailable or has failed.
• If the hurricane had already hit and caused the primary database to become unavailable, a failover would be the appropriate action.

Ensuring Continuity

In a scenario where a hurricane is approaching and you have ample time to prepare, a switchover would be the more appropriate action. This allows you to transition to the standby database smoothly and without data loss, ensuring continuous availability during the anticipated disruption.