1z0-076 Exam Dumps : Oracle Database 19c: Data Guard Administration

Based on Oracle Database 19c: Data Guard Administration documents, the three measures that can prevent clients from connecting to the wrong database instances during switchovers, failovers, or regular operations in a Data Guard environment are:

• B. The standby database services must be defined statically with the Listeners running on the standby database hosts.
• D. The client applications must use the correct TNS entries when requesting connections to the database instances.
• E. Client TNS entries for the databases use the correct service names for the intended service.
• In an Oracle Data Guard configuration, correctly configuring Oracle Net Services (including TNS entries and listeners) is crucial for ensuring that clients connect to the appropriate database instance, whether it's the primary or standby. Defining services on the standby database and associating them with listeners ensures that client applications can connect to the standby when needed, especially useful in a role transition or when the standby is open for read-only access or real-time query. It's essential that TNS entries used by client applications specify the correct service names that correspond to the intended database roles, such as primary or standby. This setup facilitates seamless connectivity to the appropriate instance based on the role, especially critical during switchovers and failovers when the roles of the databases change.
• References:Oracle's Data Guard concepts and administration guide provides extensive information on configuring network services for Data Guard environments, ensuring that applications connect to the correct database instance based on the current role of the databases in the Data Guard configuration.

To increase the number of applier processes on a logical standby database, the following changes can be made:

• C: Increasing the value for the MAX_SERVERS SQL apply parameter would allow for more applier processes to be initiated, assuming that system resources permit.
• D: Increasing the PARALLEL_MAX_SERVERS initialization parameter would allow for more parallel execution processes, which can be used by SQL apply to increase the number of applier processes.

Option A is incorrect as decreasing the number of archiver processes will not necessarily increase the number of applier processes; these are unrelated components.

Option B is incorrect because the 'FREPARER' processes do not exist, it seems to be a typographical error, and the 'REPARER' is not a valid Oracle process or parameter.

Option E is incorrect because the RECOVERY_PARALLELISM parameter controls the number of processes used for instance recovery and media recovery, not for SQL apply.

References: Oracle Data Guard Concepts and Administration guide details the configuration and tuning of SQL apply-related parameters in logical standby databases.

According to the requirements stated:

• Zero data loss must be guaranteed despite the loss of any one component: This necessitates synchronous redo transport to at least one standby database (for no data loss).
• The primary database must be protected against a regional disaster: This implies that there must be a standby database in a different region.
• Performance overhead on the primary should be minimized: This suggests that asynchronous transport should be used where possible to reduce the performance impact on the primary.
• Downtime on the primary for any reason must be kept to a minimum: This is indicative of a requirement for a fast failover mechanism, possibly with a fast-start failover (FSFO) and high availability.

Given these requirements, the appropriate option that fulfills all these is:

• Option C, where 'prima' is the primary database, 'fs1' is the Far Sync instance in the primary region, and 'physt' and 'physt2' are physical standby databases in the primary and remote regions, respectively. In this configuration:

This configuration ensures that there is zero data loss even if the primary region is completely lost, maintains performance by limiting the synchronous transport to the local region with a Far Sync instance, and has a remote standby database in a separate region for disaster recovery purposes.

References:

• Oracle Data Guard Concepts and Administration
• Oracle Data Guard Broker documentation