DBS-C01 Practice Exam 62 — 20 Questions

Question 1

A company is using Amazon DynamoDB and needs to export data to Amazon S3 for analysis. Which AWS service can perform this export without writing custom code?

Accepted Answer

AWS Glue. AWS Glue provides a built-in DynamoDB-to-S3 export feature that requires no custom code. You can create a Glue job using the 'Export DynamoDB table to S3' blueprint, which automatically handles schema inference, data conversion, and partitioning. This is the only option that directly supports the export without writing any code.

Answer

AWS Data Pipeline

Answer

Amazon EMR

Answer

DynamoDB Console

Question 2

A company is migrating an on-premises Oracle database to Amazon RDS for Oracle. The database is 2 TB in size and has a 100 Mbps internet connection. The migration must be completed within 3 days with minimal downtime. Which approach is MOST suitable?

Accepted Answer

Use AWS Database Migration Service (DMS) with a full load from an AWS Snowball device, then ongoing replication.. The 2 TB database cannot be fully loaded over a 100 Mbps internet connection within 3 days (theoretical max transfer ~2.6 TB in 3 days, but real-world throughput is lower due to overhead and contention). AWS Snowball provides a physical appliance to transfer the full load offline, bypassing bandwidth constraints, and then AWS DMS ongoing replication captures and applies changes with minimal downtime.

Answer

Export the database as a dump file, upload to S3, and restore to RDS.

Answer

Use AWS DMS with full load over the internet, then ongoing replication.

Answer

Create a VPN connection to AWS and use Oracle Data Pump over the VPN.

Question 3

A company is migrating a 2 TB on-premises Oracle database to Amazon RDS for Oracle. The migration must have minimal downtime and support ongoing replication. Which AWS service should be used to accomplish this?

Accepted Answer

AWS Database Migration Service (AWS DMS). AWS DMS is the correct choice because it supports homogeneous migrations (Oracle to Oracle) with minimal downtime through ongoing replication using change data capture (CDC). It can handle a 2 TB database by using a large enough replication instance and enabling task logging for validation, ensuring data consistency during the migration.

Answer

AWS Schema Conversion Tool (AWS SCT)

Answer

AWS DataSync

Answer

AWS Glue

Question 4

A company is migrating an on-premises MySQL database to Amazon RDS for MySQL. The database is 500 GB and the migration must have minimal downtime. Which TWO AWS services should be used together to accomplish this?

Accepted Answer

AWS Database Migration Service (AWS DMS). AWS DMS (Option D) is correct because it is purpose-built for migrating databases with minimal downtime by continuously replicating changes from the source to the target using change data capture (CDC). AWS SCT (Option E) is correct because it assesses the source MySQL schema and automatically converts any incompatible objects (e.g., storage engines, functions) to be compatible with Amazon RDS for MySQL, ensuring a smooth migration. Together, they enable a near-zero-downtime migration by first performing a full load via DMS and then applying ongoing CDC replication until cutover.

Answer

AWS App2Container

Answer

AWS CloudFormation

Answer

AWS DataSync

Question 5

A company is using Amazon Redshift for data warehousing. The security team requires that all data is encrypted at rest using a hardware security module (HSM). Additionally, the team wants to ensure that only specific IAM roles can access the database. Which configuration will meet these requirements?

Accepted Answer

Create the Redshift cluster with encryption enabled using an HSM, and attach an IAM role to the cluster to control access.. Redshift supports HSM for encryption at rest, and IAM roles can be attached to the cluster for access control. Option A is wrong because HSM and KMS are mutually exclusive. Option C is wrong because KMS does not meet the HSM requirement. Option D is wrong because encryption cannot be enabled after cluster creation.

Answer

Create the Redshift cluster with encryption enabled using a KMS key, and configure the cluster to use an HSM for key storage.

Answer

Create the Redshift cluster without encryption, then use the AWS CLI to enable encryption using a KMS key.

Answer

Create the Redshift cluster with encryption using a KMS key, and then import the HSM certificate into the cluster.

Question 6

A company is migrating a 10 TB Oracle Data Warehouse to Amazon Redshift. The source database runs on premises with limited bandwidth (100 Mbps). The migration must complete within 5 days. Which approach is most cost-effective and meets the timeline?

Accepted Answer

Use AWS Snowball Edge to transfer the initial full load, then AWS DMS for ongoing changes.. The 10 TB dataset over a 100 Mbps link would take approximately 10 days (10 TB * 8 / 100 Mbps / 86400 seconds/day) for a full load, exceeding the 5-day window. AWS Snowball Edge provides a physical, high-bandwidth transfer for the initial full load, bypassing network constraints, and AWS DMS then captures and applies ongoing changes (CDC) to keep the target in sync. This combination is the most cost-effective as it avoids expensive Direct Connect and meets the timeline.

Answer

Use AWS DMS over the internet to migrate data.

Answer

Use AWS Schema Conversion Tool (SCT) to convert and then upload to S3.

Answer

Use AWS DMS with AWS Direct Connect at 1 Gbps.

Question 7

A company has an Amazon DynamoDB table with provisioned capacity. The table experiences occasional spikes in write traffic that exceed the provisioned write capacity units (WCU). Which feature should the database specialist enable to handle these spikes without throttling?

Accepted Answer

Configure DynamoDB Auto Scaling for write capacity.. DynamoDB Auto Scaling automatically adjusts the provisioned read and write capacity based on actual traffic patterns, enabling the table to handle spikes without throttling while maintaining cost efficiency. Option A is incorrect because burst capacity provides a limited buffer for short-term spikes but can be exhausted, leading to throttling. Option C is incorrect because DAX is an in-memory cache for read operations, not writes. Option D is incorrect because switching to on-demand capacity mode can handle spikes but may result in higher costs compared to Auto Scaling with provisioned capacity.

Answer

Enable DynamoDB burst capacity.

Answer

Use DynamoDB Accelerator (DAX) to cache writes.

Answer

Switch to on-demand capacity mode.

Question 8

A company is deploying a new MySQL database on Amazon RDS. They need to ensure that the database is automatically backed up daily and retained for 30 days. Which TWO configurations should be set? (Choose 2)

Accepted Answer

Set backup retention period to 30 days.. Setting the backup retention period to 30 days ensures that automated backups are retained for the required duration. Option B is correct because automated backups must be enabled for the retention period to take effect; without enabling automated backups, no automatic daily backups occur. Together, these two settings satisfy the requirement for daily automated backups retained for 30 days.

Answer

Set backup window.

Answer

Enable Multi-AZ deployment.

Answer

Create a manual snapshot daily.

Question 9

The exhibit shows the output of an AWS CLI command for an Amazon RDS DB instance. Based on the output, what is the current configuration of the DB instance?

Accepted Answer

It is a Single-AZ MySQL DB instance.. The output shows engine=mysql, MultiAZ=false, SecondaryAvailabilityZone=null, and DBInstanceStatus=available. This indicates a Single-AZ MySQL DB instance, not a Multi-AZ deployment, not Aurora, and not in a failed state. Therefore, option D is correct.

Answer

It is an Amazon Aurora MySQL-Compatible DB cluster.

Answer

It is a MySQL DB instance that is currently in a failed state.

Answer

It is a Multi-AZ DB instance with a standby in a different AZ.

Question 10

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?

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 11

A developer runs the AWS CLI command shown in the exhibit. What is the output indicating?

Accepted Answer

The secret contains a username and password in JSON format.. The `aws secretsmanager get-secret-value` command returns the secret's value in the `SecretString` field, which typically contains a JSON object with the username and password. Option A is incorrect because the command succeeded, indicating the secret is accessible. Option B is incorrect because secrets are encrypted at rest by default. Option C is incorrect because the output includes the version ID but does not indicate rotation.

Answer

The secret value is not accessible.

Answer

The secret is not encrypted.

Answer

The secret has been rotated.

Question 12

A company is migrating an on-premises Oracle database to Amazon RDS for Oracle. The compliance team requires that all database connections use SSL/TLS and that users authenticate using IAM database authentication. The database migration is completed, but the application team reports that connections using IAM authentication are failing. The company has already enabled IAM database authentication on the RDS instance. What is the most likely cause of the failure?

Accepted Answer

The database user has not been granted the necessary privileges for IAM authentication.. IAM database authentication requires that the database user be created with the `IDENTIFIED WITH AWS_AUTHENTICATION` clause in Oracle. Without this privilege, the RDS instance will reject IAM-authenticated connections even if IAM authentication is enabled at the instance level. The application team must ensure the database user has been granted the `AWS_ORACLE_EXTENSIONS` role and that the user is mapped to an IAM policy allowing `rds-db:connect`.

Answer

The application is using an outdated root CA certificate for SSL.

Answer

The Security Group does not allow inbound traffic from the application.

Answer

The RDS instance is using a different KMS key for encryption.

Question 13

A retail company runs its inventory management system on Amazon RDS for PostgreSQL. The application performs frequent updates to inventory counts. The operations team notices that write latency increases significantly during peak sales hours. The database is a single db.r5.large instance with General Purpose SSD (gp2) storage. The CPU utilization is around 40% during peaks, but the write latency spikes. The team suspects a storage bottleneck. Which change would most effectively reduce write latency?

Accepted Answer

Change storage type to Provisioned IOPS (io2) with sufficient IOPS.. Provisioned IOPS (io2) storage provides consistent low-latency I/O performance compared to gp2, which can have variable performance due to burst credits. Option A (Multi-AZ) improves availability, not latency. Option C (read replica) offloads reads, not writes. Option D (scale up instance) increases compute capacity but may not address the I/O bottleneck if the issue is storage performance.

Answer

Enable Multi-AZ deployment.

Answer

Add a read replica to offload read traffic.

Answer

Scale up to a db.r5.xlarge instance.

Question 14

A company runs a time-series application on Amazon DynamoDB. The data has a pattern of frequent writes for recent data and rare reads for older data. They want to optimize storage costs and query performance for the time-series data. Which THREE strategies should they implement? (Choose THREE.)

Accepted Answer

Use DynamoDB Time to Live (TTL) to automatically delete old data after a certain period. DynamoDB Time to Live (TTL) automatically expires and deletes old items after a defined timestamp, reducing storage costs without manual intervention. This is ideal for time-series data where older records are rarely accessed, as TTL offloads the deletion process to DynamoDB in the background, freeing up provisioned throughput.

Answer

Increase DynamoDB read capacity units to improve query performance

Answer

Decrease DynamoDB write capacity units to reduce cost

Question 15

A retail company uses Amazon DynamoDB to store shopping cart data. The cart items are frequently updated as users add or remove products. The application reads the entire cart each time the user views it. The cart size averages 50 KB but can reach up to 400 KB. The company wants to reduce read costs and improve performance. Which design change would be most effective?

Accepted Answer

Compress the cart items before storing them in DynamoDB and decompress on read.. Compressing cart items before storing them in DynamoDB reduces the item size, which directly lowers read capacity unit (RCU) consumption since DynamoDB charges based on read item size rounded up to 4 KB increments. For a 400 KB item, compression can shrink it significantly, reducing the number of 4 KB blocks read and thus cutting costs. Decompression on read adds minimal CPU overhead but yields substantial performance gains by reducing network transfer time and read latency.

Answer

Switch to larger DynamoDB instance types to handle larger items.

Answer

Use DynamoDB Accelerator (DAX) to cache the cart data.

Answer

Normalize the cart data into separate tables for cart headers and line items.

Question 16

A company has an Amazon DynamoDB table with on-demand capacity mode. They notice that write requests are being throttled during peak hours. The table has a global secondary index (GSI) that is also throttled. Which action should the database specialist take to resolve the throttling?

Accepted Answer

Review the partition key design and consider adding a suffix to distribute writes more evenly.. The throttling of both the base table and the GSI during peak hours indicates a hot partition caused by an uneven distribution of write activity. Reviewing the partition key design and adding a suffix to distribute writes more evenly is the correct action because it addresses the root cause: DynamoDB's on-demand mode automatically scales capacity, but it cannot overcome a skewed access pattern that overloads a single partition. By spreading writes across more partitions, you eliminate the hot spot and prevent throttling without changing capacity mode.

Answer

Enable DynamoDB Streams to offload write operations.

Answer

Switch to provisioned capacity mode and increase write capacity units (WCU).

Answer

Increase the write capacity of the GSI by updating the table's provisioned throughput.

Question 17

A company is migrating a 200 GB MySQL database to Amazon Aurora MySQL. The migration must be completed within a 1-hour downtime window. Which TWO methods can achieve this?

Accepted Answer

Use Percona XtraBackup to create a physical backup, upload to S3, and restore to Aurora.. Percona XtraBackup creates a physical backup of the MySQL data files, which can be uploaded to Amazon S3 and then restored directly into an Aurora MySQL cluster. This method is significantly faster than logical backups for large databases (200 GB) because it bypasses SQL parsing and row-by-row insertion, making it feasible within a 1-hour downtime window.

Answer

Use AWS SCT to convert the schema and then perform a data load.

Answer

Use AWS DMS with full load only.

Answer

Create an RDS Read Replica of the on-premises database and promote it.

Question 18

A company is using Amazon DynamoDB with on-demand capacity mode. The application experiences occasional throttling on a table during peak hours. The table's read and write requests are within the throughput limits, but the provisioned read/write capacity is exceeded. What is the most likely cause of this throttling?

Accepted Answer

The table's previous peak throughput was lower than the current traffic, and DynamoDB is still adapting.. On-demand capacity mode in DynamoDB automatically scales based on the table's previous peak throughput. If current traffic suddenly exceeds that previous peak, DynamoDB may throttle requests until it adapts to the new traffic level, even if the requests are within the eventual on-demand limits. Option B is incorrect because although a hot partition can cause throttling, the question states that read and write requests are within the throughput limits, implying the issue is not at the partition level but rather a sudden spike beyond the adapted peak. Option C is incorrect because on-demand mode has no maximum throughput limit; it scales automatically. Option D is incorrect because on-demand mode does not use provisioned capacity; it scales without manual configuration.

Answer

The table has a hot partition that is receiving more requests than the partition can handle.

Answer

The table has exceeded the maximum allowed throughput for on-demand capacity mode.

Answer

The table's provisioned read/write capacity is set too low.

Question 19

Refer to the exhibit. A database administrator runs the AWS CLI command to check the status of an Amazon RDS MySQL DB instance. Based on the output, what action is required to apply the pending modifications?

Accepted Answer

Reboot the DB instance to apply the pending parameter group changes.. The output shows 'ParameterApplyStatus: pending-reboot', which indicates that changes to the DB parameter group (specifically the parameter modifications) require a reboot to take effect. While there are also pending modifications for the backup retention period and master user password, these do not necessitate a reboot. Therefore, the correct action is to reboot the DB instance (Option A). Options B, C, and D are incorrect: taking a snapshot is not required, modifying the parameter group has already been done (the status reflects pending-reboot), and altering the backup retention period is not the immediate action needed for the pending reboot.

Answer

Take a snapshot of the DB instance before applying changes.

Answer

Modify the DB parameter group to change the parameter values.

Answer

Modify the DB instance to set the backup retention period to 7.

Question 20

A company is migrating a 200 GB Oracle database to Amazon RDS for Oracle. Which TWO steps should be taken to ensure a successful migration? (Choose two.)

Accepted Answer

Use AWS DMS with full load and ongoing replication.. AWS DMS supports both homogeneous and heterogeneous migrations, and for a 200 GB Oracle database, using full load plus ongoing replication minimizes downtime by continuously applying changes from the source to the target RDS instance. This approach is ideal for migrating large databases with minimal disruption.

Answer

Enable TDE encryption on the source database before migration.

Answer

Use AWS DMS only for heterogeneous migrations; use Oracle Data Pump instead.

Answer

Export the database using expdp and import using impdp.