Physical Standby Protection mode

 Types of protection mode in Oracle physical standby

 

Oracle Data Guard provides different protection modes that determine the level of data protection and availability provided by the standby database. The protection mode defines how transactions are committed and synchronized between the primary and standby databases. The three primary protection modes in Oracle Data Guard are:

1. Maximum Performance (ASYNC): In Maximum Performance mode, the primary database commits transactions as soon as possible without waiting for the standby database to acknowledge the redo data. This mode offers the highest level of performance for the primary database but provides the least level of data protection. There is a potential for data loss if a primary database failure occurs before the redo data is transmitted to the standby database.

2. Maximum Availability (SYNC): In Maximum Availability mode, the primary database waits for at least one standby database to acknowledge the redo data before committing the transaction. This ensures that data is protected from the loss of a single database in the event of a failure. However, it may introduce some additional latency and potentially impact the primary database performance due to the synchronous network round-trip.

3. Maximum Protection (SYNC): In Maximum Protection mode, the primary database waits for all standby databases to acknowledge the redo data before committing the transaction. This provides the highest level of data protection but can introduce additional latency and impact the primary database performance due to the synchronous network round-trip. It ensures zero data loss in case of a single or multiple standby database failures.

In addition to these primary protection modes, Oracle Data Guard also provides a few other advanced protection modes that offer more granular control over data protection. These advanced modes include:

• Far Sync Instance: A Far Sync Instance is an intermediary instance that acts as a buffer between the primary database and remote standby databases. It provides zero data loss protection in cases where the primary and standby databases are geographically distant.

• Fast-Start Failover (FSFO): Fast-Start Failover is a feature that enables automatic failover to a standby database in case of a primary database failure. It reduces downtime and minimizes the impact on the application.

• Cascading Standby Databases: Cascading standby databases allow the creation of multiple levels of standby databases. Redo data is cascaded from the primary database to a remote standby database, and then from that standby database to another standby database. This can be used to protect against disasters that affect an entire data center or region.

Each protection mode has its own trade-offs in terms of performance, data protection, and availability. It is important to carefully evaluate the requirements and constraints of the environment to choose the appropriate protection mode that aligns with the organization's objectives and data protection needs.