DBS-C01 Management and Operations Practice Test 12 — 15 Questions

Question 1

Refer to the exhibit. An IAM policy is attached to a user who needs to manage Amazon RDS DB instances. When the user attempts to modify a DB instance, they receive an 'AccessDenied' error. What is the most likely cause?

Choose an answer to begin — your selection is scored in the full session.

Accepted Answer

The policy is missing the 'rds:ListTagsForResource' permission needed for the console.. The IAM policy attached to the user includes the 'rds:ModifyDBInstance' action, so the user should be able to modify DB instances via the API or CLI. However, the AWS Management Console frequently requires additional read-only permissions to render the interface, such as 'rds:ListTagsForResource' to display tags. Without this permission, the console may throw an 'AccessDenied' error when attempting a modification, even though the underlying modify action is allowed. This is the most likely cause of the error.

Answer

The policy does not include the 'rds:ModifyDBInstance' action for the specific DB instance ARN.

Answer

The user is trying to modify a Multi-AZ DB instance which requires additional permissions.

Answer

The policy requires a condition to allow modifications during the maintenance window.

Question 2

A company has an Amazon RDS for PostgreSQL DB instance with automated backups enabled. The retention period is set to 7 days. A developer accidentally performed a DROP TABLE operation on a critical table 2 days ago. How can the table be recovered with minimal data loss?

Accepted Answer

Perform a point-in-time restore to a time just before the DROP TABLE operation.. The correct approach is to perform a point-in-time restore (PITR) to a time just before the DROP TABLE operation. RDS for PostgreSQL with automated backups enabled supports PITR within the backup retention period (7 days). Since the table was dropped 2 days ago, restoring the DB instance to a point in time just before the drop will recover the table with minimal data loss. Option B (pg_dump) is not a suitable recovery method because it requires a pre-existing backup; it cannot generate a backup retroactively. Option C (creating a read replica and promoting it) would create a copy of the current state, which already lacks the dropped table, so it does not help. Option D (restore from oldest automated snapshot) would revert the entire database to a 7-day-old state, losing all changes made in the last 7 days, including the table that was dropped only 2 days ago, resulting in greater data loss.

Answer

Use the pg_dump utility to create a manual backup and restore it.

Answer

Create a read replica of the DB instance and promote it to a standalone instance.

Answer

Restore the DB instance from the oldest automated snapshot.

Question 3

A company runs a critical application on Amazon RDS for MySQL with Multi-AZ deployment. The application performs frequent writes. The DB instance's CPU utilization is consistently above 80%, and the write latency is high. The company wants to improve write performance without changing the application code. Which solution is MOST effective?

Accepted Answer

Migrate the database to Amazon Aurora MySQL.. Migrating to Amazon Aurora MySQL is the most effective solution because Aurora uses a distributed, SSD-backed storage system with a separate log writer process that reduces write latency. Increasing the DB instance class (Option C) can improve CPU capacity but does not address the underlying storage write latency as effectively as Aurora. Adding a read replica (Option B) offloads read traffic but does not improve write performance. Enabling Multi-AZ with synchronous replication (Option A) is already in place and can increase write latency due to synchronous replication; it does not solve the high CPU utilization issue.

Answer

Enable Multi-AZ with synchronous replication to a standby instance.

Answer

Add a read replica to offload read traffic.

Answer

Increase the DB instance class to a larger size with more vCPUs.

Question 4

A company has an Amazon DynamoDB table with on-demand capacity mode. The table experiences occasional spikes in traffic. During these spikes, some requests receive ProvisionedThroughputExceededException errors. The company wants to minimize these errors without changing the application. Which solution should be used?

Accepted Answer

Switch the table to provisioned capacity mode and enable auto scaling.. DynamoDB on-demand mode automatically scales based on traffic volume, but it has a per-partition throughput limit. During sudden traffic spikes, this limit can be exceeded, causing ProvisionedThroughputExceededException errors. Switching to provisioned capacity mode with auto scaling allows you to set a higher baseline capacity and automatically scale up to handle bursts, reducing the likelihood of hitting per-partition limits. Option B (DAX) only helps with read caching, not write throughput. Option C (manually increasing capacity) is not applicable in on-demand mode and would not auto-scale. Option D (global tables) replicates data across regions for disaster recovery, not for increasing throughput in a single region.

Answer

Enable DynamoDB Accelerator (DAX) for caching.

Answer

Increase the read and write capacity units manually.

Answer

Use DynamoDB global tables to distribute the load across multiple regions.

Question 5

A company runs an Amazon RDS for SQL Server DB instance in a VPC. The security group for the DB instance allows inbound traffic on port 1433 from the application servers' security group. The application servers can connect to the database, but a database administrator cannot connect from their workstation using SQL Server Management Studio (SSMS). What is the MOST likely cause?

Accepted Answer

The security group does not allow inbound traffic from the DBA workstation's IP address.. The DBA's workstation is not within the VPC, so it needs a public IP and the security group must allow inbound traffic from the workstation's IP. Option A (DBA's IP not in security group) is correct. Option B (SSMS version) is unlikely; Option C (Multi-AZ) irrelevant; Option D (encryption) does not prevent connection.

Answer

The DBA is using an incompatible version of SSMS.

Answer

The DB instance is configured as Multi-AZ, which restricts direct connections.

Answer

The DB instance has encryption enabled, which blocks non-encrypted connections.

Question 6

A database administrator notices that an Amazon RDS for MySQL DB instance has experienced a failover during a maintenance window. What is the most likely cause of this failover?

Accepted Answer

A system update was applied during the maintenance window, causing a reboot. The RDS maintenance window is used to apply system updates, which may require a reboot and failover if Multi-AZ is enabled. Option A is wrong because running out of storage does not cause a failover; instead, it would cause the instance to become unavailable. Option B is wrong because promoting a read replica is a manual action, not an automatic failover during maintenance. Option C is wrong because a manual failover is initiated by the administrator, not automatically during the maintenance window.

Answer

The DB instance ran out of storage and automatically failed over

Answer

A read replica was promoted to a primary instance

Answer

A manual failover was initiated by the administrator

Question 7

A company runs an Amazon RDS for PostgreSQL DB instance with Multi-AZ enabled. The primary instance is in us-east-1a and the standby is in us-east-1b. During a routine audit, the security team discovers that database connections are being terminated unexpectedly. The database administrator reviews the RDS events and sees an event: 'A Multi-AZ failover has been completed.' What step should be taken to determine the cause of this failover?

Accepted Answer

Review RDS events and AWS CloudTrail logs for API calls related to the failover. Reviewing RDS events and AWS CloudTrail logs is the correct step because these services record detailed information about the failover, including any API calls that may have triggered the failover or underlying issues. Option A is incorrect because CloudWatch metrics show resource utilization (CPU, memory) but do not directly indicate the cause of a failover. Option B is incorrect because maintenance windows are scheduled events; although they may cause failovers, simply checking the console for maintenance windows does not provide a definitive cause for an unexpected failover. Option D is incorrect because the describe-db-instances CLI command shows the current status of instances (e.g., whether the standby is available) but does not provide historical information about why the failover occurred.

Answer

Examine Amazon CloudWatch metrics for increased CPU or memory usage

Answer

Check the RDS console for maintenance windows

Answer

Run the describe-db-instances CLI command to check the status of the standby

Question 8

A database team is migrating an on-premises Oracle database to Amazon Aurora PostgreSQL. The team needs to ensure minimal downtime and data consistency. Which approach should be used?

Accepted Answer

Use AWS Database Migration Service (DMS) with ongoing replication using change data capture (CDC). AWS DMS with ongoing replication using change data capture (CDC) is the correct approach because it enables a live migration with minimal downtime. DMS can perform a full load of the Oracle database and then continuously replicate ongoing changes from Oracle to Aurora PostgreSQL, ensuring data consistency at the point of cutover. This method avoids the need for a long maintenance window and supports heterogeneous migrations with automatic schema conversion.

Answer

Use the PostgreSQL foreign data wrapper (FDW) to link the Oracle database

Answer

Use AWS Server Migration Service (SMS) to replicate the database

Answer

Use pg_dump and pg_restore to migrate the data during a maintenance window

Question 9

A company has an Amazon DynamoDB table with on-demand capacity mode. The table experiences a sudden spike in traffic, and the application starts receiving ProvisionedThroughputExceededException errors. What is the most likely cause?

Accepted Answer

The traffic spike exceeded the previous peak traffic by more than double in a short period. DynamoDB on-demand capacity mode can throttle requests if the traffic spike exceeds the previous peak traffic by more than double within a short period. This is due to the adaptive capacity mechanism that requires time to scale. Option A is wrong because on-demand mode does not have provisioned read/write capacity units. Option B is wrong because on-demand mode does not have a maximum number of capacity units; it scales automatically but with a ramp-up limit. Option D is wrong because Auto Scaling is not applicable to on-demand mode; it uses a different scaling model.

Answer

The provisioned read capacity units are insufficient

Answer

The table has reached the maximum number of read capacity units

Answer

Auto Scaling is not configured to increase capacity

Question 10

A company is using Amazon RDS for SQL Server with Multi-AZ and automated backups enabled. The database administrator needs to restore the database to a specific point in time that is within the retention period. What is the correct procedure?

Accepted Answer

Use the RDS console to perform a point-in-time recovery to the desired time. The correct procedure for performing a point-in-time recovery within the retention period for an Amazon RDS for SQL Server instance with Multi-AZ and automated backups is to use the RDS console or API to specify the desired point in time. This restores the database to the specified time using the automated backup logs. Option B is incorrect because manual snapshots capture a specific point and cannot be used for arbitrary point-in-time recovery. Option C is incorrect because native SQL Server backup is not supported for RDS instances; AWS manages backups. Option D is incorrect because restoring from the latest automated snapshot does not give a specific point in time.

Answer

Restore from a manual snapshot taken at the desired time

Answer

Use the native SQL Server backup and restore functionality

Answer

Restore from the latest automated snapshot

Question 11

An Amazon RDS for MySQL DB instance has a high number of connections and the application is experiencing slow response times. The database administrator wants to identify the queries that are causing the most load. Which approach is most effective?

Accepted Answer

Enable Amazon RDS Performance Insights and review the top SQL queries. Performance Insights provides a dashboard to identify top queries by load. Option A is wrong because it shows connections, not query performance. Option B is wrong because CloudWatch logs show slow queries but not in real-time. Option D is wrong because RDS events show instance events, not query load.

Answer

Enable slow query logs and analyze them in CloudWatch Logs

Answer

Monitor the DatabaseConnections metric in CloudWatch

Answer

Check RDS events for any error messages

Question 12

A company is using Amazon DynamoDB with global tables (multi-region) for a gaming application. The application writes to a table in us-east-1 and reads from a table in eu-west-1. The team notices that writes in us-east-1 are taking longer than expected to propagate to eu-west-1. What is the most likely cause?

Accepted Answer

Network latency between the regions is causing replication delay. DynamoDB global tables use asynchronous replication across regions, and network latency between regions is the primary factor causing delays in propagation. Option B is incorrect because read and write capacity is independent per region; insufficient capacity in eu-west-1 does not affect replication speed from us-east-1. Option C is incorrect while conflict resolution can occur with concurrent writes, it does not inherently cause delays; replication delay is due to network latency. Option D is incorrect because DynamoDB Streams are required for global tables to function; if they were disabled, replication would not occur at all, not just be delayed.

Answer

The write capacity in eu-west-1 is insufficient

Answer

Conflicts are being resolved due to concurrent writes

Answer

DynamoDB Streams is disabled on the table

Question 13

A company is using Amazon ElastiCache for Redis to cache database query results. The application team reports that cache hit ratio has dropped significantly. What is the first step to investigate?

Accepted Answer

Check the CacheHitRate and Evictions metrics in CloudWatch. When the cache hit ratio drops significantly, the first step is to investigate whether the cache is evicting keys due to memory pressure or if the working set no longer fits. CloudWatch metrics such as `CacheHitRate` and `Evictions` provide immediate visibility into these conditions without requiring direct Redis access. This aligns with the AWS Well-Architected Framework's principle of observability before making configuration changes.

Answer

Run the Redis INFO command to see memory usage

Answer

Review the ElastiCache event logs for node failures

Answer

Check the Redis AOF persistence logs

Question 14

An Amazon RDS for Oracle DB instance is experiencing high swap usage. The database administrator wants to reduce swap usage. Which action should be taken?

Accepted Answer

Increase the DB instance class to a larger size with more memory. High swap usage on an Amazon RDS for Oracle DB instance indicates that the operating system is using disk-based swap space as a substitute for physical RAM, which severely degrades database performance. Increasing the DB instance class to a larger size with more memory directly addresses the root cause by providing additional RAM, reducing or eliminating the need for swapping. This is the correct action because swap usage is a memory pressure issue, not a storage or availability problem.

Answer

Change the storage type from gp2 to io1

Answer

Delete archived redo logs to free up space

Answer

Enable Multi-AZ to distribute the load

Question 15

Which TWO actions can be taken to monitor the health of an Amazon DynamoDB table? (Choose 2.)

Accepted Answer

Enable Amazon CloudWatch metrics for the table. Enabling CloudWatch metrics for a DynamoDB table provides key health indicators such as read/write capacity utilization, throttled requests, and latency. Option E is correct because setting up CloudWatch alarms on ThrottledRequests allows you to proactively detect and respond to throttling events, which directly impacts table health. Option A is incorrect because AWS Trusted Advisor checks overall account limits but does not provide real-time health monitoring of a specific table. Option C is incorrect because DynamoDB Streams capture item-level changes for event-driven processing, not for monitoring the table's operational health. Option D is incorrect because DAX is an in-memory cache that improves read performance, not a monitoring tool.

Answer

Use AWS Trusted Advisor to check table limits

Answer

Enable DynamoDB Streams and process events with AWS Lambda

Answer

Use DynamoDB Accelerator (DAX) to improve response times