1z0-076 Practice Exam Questions with Answers Oracle Database 19c: Data Guard Administration Certification

In the context of Oracle Data Guard and Global Database Services (GDS):

• DGMGRL may be used to add the Sales configuration to the Prod pool in gds (A): Data Guard Broker's command-line interface DGMGRL can be utilized to manage configurations with GDS, allowing the addition of Data Guard Broker configurations to GDS pools.
• Performing a role change with DGMGRL automatically notifies GDS which in turn activates the appropriate services (B): When a role change is executed using DGMGRL, GDS is automatically notified, and it then activates the services that are appropriate for the new database roles.
• DGMGRL may be used to add a single database to the Sales configuration even if Sales is a member of the Prod pool (C): DGMGRL provides the capability to manage individual databases within a broker configuration, including adding databases to a configuration that is already part of a GDS pool.References:
• Oracle Data Guard Broker documentation
• Oracle Global Data Services documentation

When a physical standby database is opened in real-time query mode, which may be referred to as real-time apply when using Active Data Guard, certain operations can disrupt ongoing sessions. However, with features like Application Continuity and the proper configuration of initialization parameters such as STANDBY_DB_PRESERVE_STATES, user sessions and current buffers may be preserved during role transitions such as a switchover or failover. Specifically, the STANDBY_DB_PRESERVE_STATES parameter can be set to preserve none, all, or only user sessions during such transitions. This ensures that in-flight transactions are not lost and that users do not experience disruptions during the role transitions of a physical standby database????.

References

• Oracle Data Guard Concepts and Administration??
• Oracle Database Licensing Information User Manual??
• Oracle Data Guard Broker User Manual?

When issuing a "switchover to sheep;" command in a Data Guard configuration, the primary database (Dogs) transitions to a standby role, and the target standby database (Sheep) becomes the new primary database. Fast-Start Failover (FSFO) remains enabled, but its target changes according to the new roles of the databases. Since Cats is also a physical standby database, it does not become the failover target by default unless it is specified in the broker configuration. After the switchover, the original primary (Dogs) becomes the new standby database and thus the new failover target for FSFO.References:Oracle Data Guard Broker documentation provides detailed procedures and explanations of switchover operations, including how FSFO targets are affected post-switchover. This behavior is consistent across different Oracle Database versions that support Data Guard and FSFO.

C. The LGWR (Log Writer) process is responsible for writing redo entries from the redo log buffer to the online redo log files on the primary database. This is a fundamental process in the Oracle Database architecture, ensuring that all changes made to the database are captured for purposes such as recovery, replication, and high availability.

D. Real-time apply on a logical standby database requires standby redo log files. The standby redo log files are used to store redo data received from the primary database before it is applied to the logical standby database. This enables the logical standby to apply changes as they are received, without waiting for the current redo log file to be archived.

E. Similarly, on a physical standby database, standby redo log files are used for real-time apply. They store redo data from the primary database, allowing the physical standby to apply redo data concurrently as it is received, rather than waiting for redo log files to be archived. This capability is crucial for maintaining a physical standby database that is closely synchronized with the primary database with minimal lag.

These functionalities are integral to Oracle Data Guard configurations and are not dependent on Oracle Streams or Oracle GoldenGate, which are separate technologies for data replication and integration????.

Asynchronous redo transport is a method where the primary database does not wait for an acknowledgment from the standby database before committing transactions, which helps in minimizing the impact on the primary database's performance (B). This transport mode is associated with the Maximum Performance data protection mode, which prioritizes performance over synchronicity of data between the primary and standby databases (C). While it provides a level of data protection, there could be some data loss in the event of a primary database failure because redo data may not have been transmitted to the standby database at the time of the failure.

References:Oracle Data Guard Concepts and Administration documentation provides detailed explanations of different redo transport modes and their implications on data protection and performance. Asynchronous transport mode's behavior and association with Maximum Performance mode are outlined explicitly.

When enabling fast-start failover, certain conditions must be met:

• The fastStartFailoverTarget property is not set on Dogs (A): The primary database (Dogs) needs to have a fast-start failover target configured for the operation to succeed.
• The LogXptMode property is set to ASYNC on Sheep while Sheep is the target standby database (B): Fast-start failover requires synchronous redo transport (SYNC or FASTSYNC) to ensure zero data loss, which is a prerequisite for enabling the feature.
• The LogXptMode property is set to ASYNC on Dogs (D): Similar to the previous point, the primary database must be configured to use synchronous redo transport for the fast-start failover to be possible.References:
• Oracle Data Guard Broker documentation
• Oracle Database Error Messages Guide

To automate the instantiation of a PDB in the standby database after creating a remote clone in the primary database, certain conditions must be met:

• Open PDBI (remote clone source) in Read Only (A): The source PDB from which the clone is created must be open in read-only mode to ensure a consistent state during cloning.
• Set STANDBY_PDB_SOURCE_FILE_DIRECTORY to in the london database (C): This parameter specifies the location on the standby database where the files from the source PDB should be placed.
• Set STANDBY_FILE_MANAGEMENT to auto in the london database (F): This parameter automates the management of file changes on the standby database when structural changes occur on the primary database, ensuring that the clone operation is reflected automatically on the standby.References:
• Oracle Multitenant Administrator's Guide
• Oracle Data Guard Broker documentation

• A static service must be registered with the local listener to enable DGMGRL to restart instances during the course of broker operations (A): For DGMGRL (Data Guard Manager Command-Line Interface) to perform instance management operations, such as restarting instances, a static service registration in the listener is required. This allows the broker to connect to the database instance even when the instance is not fully up and the dynamic service registration is not available.
• Installing the oracle-database-preinstall-19c package is NOT sufficient to set up operating system kernel parameters for Oracle Net (C): While the oracle-database-preinstall-19c package automates the setting of several kernel parameters to meet the preinstallation requirements for Oracle Database, it does not specifically tailor all settings for Oracle Net in a Data Guard configuration. Additional manual configuration may be required to optimize Oracle Net services for Data Guard operations.

References:

• Oracle Data Guard Broker documentation
• Oracle Net Services Administrator's Guide

The rate of SQL apply on a logical standby database can be influenced by:

• A: The number of PREPARER processes (which seems to be a typographical error and should read as PREPARER or similar) which prepare the redo data for the applier processes.
• B: The number of coordinator processes on the standby database instance which coordinate the SQL apply activities.
• C: The number of full table scans performed by SQL apply since full table scans can be resource-intensive and slow down the apply rate.
• E: The number of applier processes which apply the redo data to the logical standby database.

Option D is incorrect as the size of the undo tablespace on the logical standby database is more likely to affect the SQL apply lag rather than the rate of SQL apply.

Option F is incorrect because the size of the shared pool would typically not influence the rate of SQL apply. The shared pool is more related to the caching of shared SQL and PL/SQL code and control structures.

References: Oracle's documentation on SQL Apply in Data Guard configurations discusses the factors affecting the performance of SQL Apply operations on logical standby databases.

Data Guard Broker is a management tool that simplifies the configuration, management, and monitoring of Data Guard environments. The prerequisites for using Data Guard Broker include:

• The primary and standby databases must run the same version of the Oracle Database server (A): This ensures compatibility between the primary and standby databases and enables seamless role transitions and data synchronization.
• Network connectivity to the primary database instance must be defined on the servers hosting the standby database instances (B): Proper network connectivity is essential for communication between the primary and standby databases, allowing for the replication of data and the synchronization of changes.
• If any database in the configuration is a RAC database, then the broker configuration files must reside in shared storage accessible by all database instances for all databases in the broker configuration (D): In Real Application Clusters (RAC) environments, shared storage ensures that all instances of the RAC database can access the broker configuration files, facilitating the management of the Data Guard environment across all instances.References:
• Oracle Data Guard Broker documentation
• Oracle Real Application Clusters Administration and Deployment Guide

A Physical Standby Database can indeed be converted into a Logical Standby Database, providing flexibility in a Data Guard configuration. This allows for the database to switch roles and supports SQL apply operations, enabling more granular control over the data and transactions being replicated and applied. Additionally, having a configuration with a primary database and one or more physical standby databases allows for rolling upgrades to be performed. This means that each database in the Data Guard configuration can be upgraded in a phased manner, minimizing downtime and ensuring high availability during the upgrade process????.

Global Sequences are Oracle sequences that generate unique values across multiple instances in an Oracle RAC or a Data Guard configuration. Regarding their behavior and performance when connected to a physical standby database with Real-Time Query enabled:

• A: The usage of Global Sequences can indeed have a performance impact on the primary database due to the need to generate unique values that are consistent across both primary and standby databases.
• D: The performance impact on the physical standby database may occur if the CACHE size is too small. This is because the standby database will frequently have to access the primary database to replenish the cache, which can increase the load and potentially lead to performance degradation.
• E: Global Sequences should have the NOORDER and CACHE options set. The NOORDER option ensures that sequence numbers are provided without guaranteeing sequence order, thus improving scalability and performance. The CACHE option is used to specify how many sequence values will be held in memory for faster access.

Option B is incorrect as the LOG_ARCHIVE_DEST_n parameter's definition for standbys pointing back to the primary does not directly pertain to the creation of sequences.

Option C is incorrect because there is no requirement that the size of the cache for a sequence must be at least 100. The CACHE size can be set to a different number based on specific use cases or performance considerations.

References: Oracle's documentation on sequences and their behavior in a Data Guard environment provides insights into the performance considerations and best practices for using sequences, particularly in a Real-Time Query context.

After a successful failover to the 'cats' database in a Data Guard configuration:

• B: Sheep, being another standby database, would typically remain in the enabled state unless specifically disabled or if there was a configuration issue.
• D: Dogs, which was the primary database prior to failover, will be in a disabled state as part of the failover process. Manual intervention is required to re-establish 'dogs' as a standby database or to return it to the primary role through another role transition.
• E: If the configuration was in Maximum Availability mode before failover, it would remain in this mode after failover, provided all settings were properly configured and no changes were made to the protection mode.

Option A is incorrect because failover does not automatically change the protection mode to Maximum Performance. The protection mode remains as it was prior to the failover unless manually altered.

References: The behavior of Oracle Data Guard during failover and the resulting configuration state is described in the Oracle Data Guard Broker documentation.

After a successful switchover operation in a Data Guard environment, the new primary database (the former standby) will be open read-write (option A). If the former primary database transitions to a logical standby database, it will also be open read-write (option C), allowing it to apply redo data while servicing read-only queries. The former primary, if converted to a physical standby, will adopt the state that the former physical standby database was in prior to the switchover, which can vary based on the configuration prior to the switchover (option D). The state of a physical standby database can range from mounted to open read-only, depending on whether Real-Time Query was enabled. Thus, the exact state will depend on the pre-switchover setup. It's also essential to highlight that options B and E suggest specific states for a former primary turned logical standby, and a former primary turned physical standby, respectively, but these states are not fixed and depend on the configurations set up by the database administrators. References: The answers are corroborated by Oracle's documentation on Data Guard switchovers, specifically in the Oracle Data Guard Concepts and Administration guide, which explains the roles and states of databases in a Data Guard configuration before and after switchovers.

Block change tracking is a feature that enhances the efficiency of incremental backups by recording changed blocks in a tracking file. When used with Oracle Active Data Guard:

• It starts the RVWR process on the physical standby database instance (A): When block change tracking is enabled on a physical standby database, the Recovery Writer (RVWR) process is initiated. This process is responsible for recording the changes to blocks in the block change tracking file, which is then used to optimize incremental backups.
• It allows fast incremental backups to be offloaded to the physical standby database (E): With block change tracking enabled on the physical standby database, fast incremental backups can be offloaded from the primary database. This reduces the workload on the primary database and utilizes the standby database for backup operations, improving overall system performance and efficiency.References:
• Oracle Database Backup and Recovery User's Guide
• Oracle Active Data Guard documentation