DBS-C01 Management and Operations Practice Test 17 — 15 Questions

Question 1

A database administrator is troubleshooting a backup failure for an Amazon RDS for SQL Server DB instance. The error message states 'Insufficient storage capacity for backup. Free storage space is 0 GB.' The DB instance has 200 GB allocated storage. What is the most likely cause?

Accepted Answer

The DB instance has insufficient free storage space to perform the backup.. Option A is correct because RDS requires free storage for automated backups and logs; insufficient free storage causes backup failure. Option B is wrong because backup retention does not consume storage. Option C is wrong because snapshot storage is separate. Option D is wrong because transaction logs accumulate in allocated storage.

Answer

The DB instance has reached the maximum number of manual snapshots.

Answer

The transaction logs are consuming all allocated storage.

Answer

The backup retention period is set to 0 days, disabling automated backups.

Question 2

A company has an Amazon Aurora MySQL DB cluster with a single writer and two readers. The writer instance fails, and the failover mechanism promotes one of the readers to writer. The application, which uses a custom connection pool, continues to experience errors for several minutes. What should the database administrator do to minimize downtime during future failovers?

Accepted Answer

Modify the application to use the cluster endpoint instead of the instance endpoint.. Option B is correct because using the cluster endpoint ensures automatic routing to the current writer. Option A is wrong because DNS caching is fixed by using cluster endpoint. Option C is wrong because increasing pool reduces latency but not failover detection. Option D is wrong because Multi-AZ is already used.

Answer

Increase the connection pool size to handle more connections.

Answer

Configure the application to use the reader endpoint for all traffic.

Answer

Enable Multi-AZ on the Aurora cluster.

Question 3

A development team is using Amazon DynamoDB with on-demand capacity mode for a new application. During initial testing, they notice that write requests are occasionally throttled during traffic bursts. They have enabled DynamoDB Accelerator (DAX) for read-heavy operations. What is the best recommendation to eliminate write throttling?

Accepted Answer

Review the table's partition key design to avoid hot keys.. Option D is correct because on-demand capacity can handle spikes, but if throttling still occurs, there may be a hot partition. Option A is wrong because DAX only caches reads. Option B is wrong because adaptive capacity helps but may not eliminate throttling for extremely skewed access. Option C is wrong because on-demand is already enabled; throttling indicates a design issue.

Answer

Enable DynamoDB adaptive capacity to automatically adjust partition throughput.

Answer

Switch to provisioned capacity mode with Auto Scaling.

Answer

Increase the DAX cluster node size to handle more write traffic.

Question 4

A company's Amazon RDS for Oracle instance is running out of storage space. The database administrator wants to add storage without downtime. Which action should be taken?

Accepted Answer

Use the 'Modify DB Instance' action to increase the allocated storage.. Option C is correct because RDS supports modifying allocated storage online with minimal downtime. Option A is wrong because creating a new instance and migrating involves downtime. Option B is wrong because increasing storage is not a backup. Option D is wrong because deleting logs may cause issues.

Answer

Delete old archived redo logs to free up space.

Answer

Take a snapshot and restore to a larger instance.

Answer

Create a new DB instance with larger storage and migrate the data.

Question 5

A database administrator needs to audit all SQL queries executed on an Amazon RDS for PostgreSQL instance, including SELECT statements. What is the most efficient way to achieve this?

Accepted Answer

Install the pgAudit extension and configure it to log all statements.. Option D is correct because enabling pgAudit extension logs all queries including SELECT. Option A is wrong because CloudTrail does not capture SQL queries. Option B is wrong because enhanced monitoring does not log queries. Option C is wrong because database logs may not capture all queries without audit extension.

Answer

Enable AWS CloudTrail for the RDS instance.

Answer

Configure the DB instance to export logs to Amazon CloudWatch Logs.

Answer

Enable Enhanced Monitoring for the DB instance.

Question 6

A company is using Amazon DynamoDB with provisioned capacity and Auto Scaling. They notice that during a marketing campaign, write traffic exceeded the provisioned WCU and caused throttling. Auto Scaling increased the WCU, but the throttling persisted for several minutes. Which additional measure can prevent throttling during such predictable spikes?

Accepted Answer

Configure a scheduled scaling action in Application Auto Scaling to increase WCU before the campaign.. Option A is correct because using Application Auto Scaling scheduled scaling allows pre-scaling capacity before the spike. Option B is wrong because DAX is for reads. Option C is wrong because on-demand may be costlier but solves unpredictability; for predictable spikes, scheduled scaling is better. Option D is wrong because increasing max capacity alone doesn't pre-scale.

Answer

Switch the table to on-demand capacity mode.

Answer

Enable DynamoDB Accelerator (DAX) to cache write requests.

Answer

Increase the maximum provisioned WCU in the Auto Scaling policy.

Question 7

A company is running an Amazon RDS for MySQL instance with Multi-AZ. The primary instance in us-east-1a fails, and the standby in us-east-1b is promoted. The application cannot connect after failover. Which TWO steps should the database administrator take to restore connectivity?

Accepted Answer

Update the application's connection string to point to the new writer endpoint.. Option A is correct because the CNAME updates automatically, but DNS caching may cause delays. Option D is correct because updating the connection string to the new writer endpoint ensures connectivity. Option B is wrong because rebooting the new primary is not required. Option C is wrong because modifying security group is unnecessary; it already allows traffic. Option E is wrong because read replicas are not related.

Answer

Reboot the new primary instance to reset connections.

Answer

Update the security group to allow inbound traffic from the application.

Answer

Create a read replica and promote it to a new primary.

Question 8

A company is migrating an on-premises Oracle database to Amazon RDS for Oracle. The database is 2 TB in size and has a tight migration window of 8 hours. Which THREE steps should be taken to minimize downtime during the migration?

Accepted Answer

Use AWS Database Migration Service (AWS DMS) with ongoing replication.. Option B is correct because AWS DMS can perform continuous replication. Option C is correct because using a large instance reduces migration time. Option E is correct because disabling backups during migration reduces overhead. Option A is wrong because AWS SCT is for schema conversion, not data migration. Option D is wrong because manual snapshot is for backup, not migration.

Answer

Take a manual snapshot of the source database before migration.

Answer

Use AWS Schema Conversion Tool (AWS SCT) to convert the schema.

Question 9

A company uses Amazon DynamoDB for a gaming application. During a new game launch, the application experiences high latency and throttling on a table with a partition key of 'user_id' and a sort key of 'timestamp'. The access pattern is to query recent items for a given user. Which TWO design changes can improve performance?

Accepted Answer

Use a composite key with 'game_id' as partition key and 'timestamp' as sort key.. Option A is correct because using a Global Secondary Index (GSI) with a different key can distribute traffic. Option D is correct because adding a GSI with 'game_id' as partition key can distribute writes if 'game_id' has high cardinality. Option B is wrong because increasing read capacity doesn't solve hot partition issues. Option C is wrong because simple queries are fine. Option E is wrong because DAX caches reads, not writes.

Answer

Use strongly consistent reads for all queries.

Answer

Increase the provisioned read capacity for the table.

Answer

Enable DynamoDB Accelerator (DAX) to cache write operations.

Question 10

A company is running an Amazon RDS for MySQL DB instance. The database performance has degraded over time, and the company suspects that slow queries are the cause. Which AWS service should the company use to identify the slow queries and analyze the database performance?

Accepted Answer

Amazon RDS Performance Insights. Performance Insights provides a dashboard to analyze database performance and identify slow queries. CloudWatch Logs (A) is for logs, not query analysis. RDS Enhanced Monitoring (B) provides OS metrics, not query details. AWS Trusted Advisor (D) provides best-practice checks, not query analysis.

Answer

AWS Trusted Advisor

Answer

Amazon RDS Enhanced Monitoring

Answer

Amazon CloudWatch Logs

Question 11

A company is migrating its on-premises Oracle database to Amazon RDS for Oracle. The database is 2 TB in size and has a 24-hour maintenance window. The company needs to minimize downtime during the migration. Which AWS service should be used to perform the migration with minimal downtime?

Accepted Answer

AWS Database Migration Service (AWS DMS). AWS DMS supports homogeneous and heterogeneous migrations with minimal downtime by replicating ongoing changes. RDS for Oracle does not support native Oracle Data Guard (B) across environments. AWS SCT (C) is for schema conversion, not full data migration. AWS Database Migration Service (D) is the recommended service, but option A is AWS DMS which is correct.

Answer

AWS Database Migration Service

Answer

Oracle Data Guard

Answer

AWS Schema Conversion Tool (AWS SCT)

Question 12

A company has a production Amazon RDS for PostgreSQL Multi-AZ DB instance. The company's security team requires that all database connections use IAM database authentication. The company also needs to ensure that connections from a specific application server are allowed only if the server has a valid IAM role. Which combination of steps should the database administrator take to meet these requirements?

Accepted Answer

Enable IAM database authentication on the RDS instance. Create a database user that matches the IAM role ARN. Grant the application server's IAM role the rds_iam role. Configure the application to generate an authentication token using the IAM role's credentials.. IAM database authentication requires mapping IAM users/roles to database users and enforcing SSL. Steps: 1) Enable IAM DB authentication on the RDS instance. 2) Create a database user that matches the IAM role ARN. 3) Grant the application server's IAM role permission to connect. 4) Configure the application to use an authentication token. The correct answer is A because it includes enabling IAM auth, creating the database user, and configuring the application. Option B is wrong because it uses the IAM user ARN instead of the role ARN. Option C is wrong because it does not enable IAM auth. Option D is wrong because it uses a password.

Answer

Create a database user with a strong password. Enable IAM database authentication. Assign the application server an IAM policy that allows rds-db:connect. Configure the application to use the password.

Answer

Enable IAM database authentication. Create a database user matching the IAM user ARN. Grant the application server's IAM user the rds_iam role. Configure the application to use an authentication token.

Answer

Enable IAM database authentication. Create a database user that matches the IAM role ARN. Configure the application to use the database master username and password.

Question 13

A company is using Amazon DynamoDB for a web application. The company notices that read requests to a particular table are throttled during peak hours. The table has a provisioned read capacity of 1000 read capacity units (RCUs). The read requests are mostly eventually consistent reads. What should the company do to reduce throttling without changing the application code?

Accepted Answer

Increase the provisioned read capacity for the table.. Increasing the provisioned read capacity directly addresses throttling by allowing more reads per second. Option B is wrong because DynamoDB Accelerator (DAX) requires code changes to use. Option C is wrong because eventually consistent reads are already used. Option D is wrong because using strongly consistent reads would increase RCU consumption, worsening throttling.

Answer

Use Amazon ElastiCache to cache the read results.

Answer

Switch to strongly consistent reads to reduce the number of read requests.

Answer

Implement DynamoDB Accelerator (DAX) to cache read requests.

Question 14

A company is running an Amazon RDS for SQL Server DB instance. The company needs to capture changes to a specific table and replicate them to an Amazon S3 bucket in near real time. Which AWS service should be used to achieve this?

Accepted Answer

AWS Database Migration Service (AWS DMS) with ongoing replication. AWS DMS with ongoing replication (change data capture) can capture changes and replicate them to S3. Option B (AWS Glue) is for ETL jobs, not real-time CDC. Option C (Amazon Kinesis Data Streams) could ingest data but requires additional configuration. Option D (Amazon RDS for SQL Server replication) does not directly write to S3.

Answer

AWS Glue

Answer

Amazon RDS for SQL Server native replication

Answer

Amazon Kinesis Data Streams

Question 15

A company runs a critical application on an Amazon RDS for MySQL DB instance. The company requires that the database be available with minimal downtime during a disaster recovery scenario. The current RDS instance is in us-east-1. The company wants to have a standby database in us-west-2 with automatic failover. What should the company do to meet this requirement?

Accepted Answer

Create a cross-region read replica in us-west-2. Configure automatic failover using Amazon Route 53 health checks.. An RDS cross-region read replica can be promoted to a standalone instance in a disaster. Option A (Multi-AZ in us-east-1) does not provide cross-region failover. Option B (snapshots) has downtime. Option D (Multi-AZ in us-west-2) does not help if us-east-1 fails.

Answer

Create a Multi-AZ deployment in us-west-2 and use Amazon Route 53 to failover.

Answer

Take daily snapshots and copy them to us-west-2. Restore from snapshot in us-west-2 during a disaster.

Answer

Create a Multi-AZ deployment in us-east-1.