DBS-C01 Deployment and Migration Practice Test 25 — 15 Questions

Question 1

A company wants to migrate its Oracle data warehouse to Amazon Redshift. The source database is 10 TB and has many complex stored procedures. Which AWS service should be used primarily for converting the stored procedures to Amazon Redshift compatible code?

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

Accepted Answer

AWS Schema Conversion Tool (AWS SCT). AWS Schema Conversion Tool (AWS SCT) is the correct choice because it is specifically designed to convert database schemas and complex code objects, such as stored procedures, functions, and packages, from one database engine to another. For an Oracle-to-Amazon Redshift migration, AWS SCT can automatically translate Oracle PL/SQL stored procedures into Amazon Redshift compatible SQL (e.g., using PL/pgSQL or SQL functions), handling syntax differences and unsupported features. This makes it the primary tool for converting the 10 TB data warehouse's stored procedures, whereas other services focus on data movement or ETL, not schema and code conversion.

Answer

AWS Glue

Answer

AWS Database Migration Service (AWS DMS)

Answer

Amazon Redshift COPY command

Question 2

A company is migrating a 5 TB MySQL database to Amazon Aurora MySQL. The migration must have zero downtime and the source database is continuously written to. The team plans to use AWS DMS with ongoing replication. However, they notice that the target Aurora instance is not receiving all changes from the source. Which configuration change is most likely required to resolve this?

Accepted Answer

Enable binary logging (binlog) on the source MySQL database with row-based logging.. AWS DMS requires binary logging (binlog) with row-based logging on the source MySQL database to capture ongoing changes for continuous replication. Without binlog enabled, DMS cannot read the change data stream needed to replicate transactions to the target Aurora instance, causing missed changes. This is a mandatory prerequisite for any MySQL-to-Aurora migration using DMS with ongoing replication.

Answer

Create an Amazon RDS read replica of the source database and use it as the source endpoint.

Answer

Set the target table preparation mode to 'Do nothing' in the DMS task.

Answer

Configure a VPC endpoint for the DMS replication instance.

Question 3

A company is migrating a 500 GB Oracle database to Amazon RDS for Oracle. They want to minimize downtime and use AWS DMS for ongoing replication. The source database is in a corporate data center behind a firewall. What is the recommended network setup for the DMS replication instance?

Accepted Answer

Deploy the DMS replication instance in a VPC that has a VPN or AWS Direct Connect connection to the corporate data center.. AWS DMS requires network connectivity between the replication instance and both the source and target databases. Since the source Oracle database is behind a corporate firewall, the DMS replication instance must be deployed in a VPC that has a VPN or AWS Direct Connect connection to the corporate data center. This establishes a private, secure, and low-latency network path for ongoing replication, minimizing downtime during migration.

Answer

Launch the DMS replication instance with a public IP address and allow inbound traffic from the corporate firewall.

Answer

Create a VPC endpoint for the DMS service and route traffic through it.

Answer

Install the DMS replication software on a server in the corporate data center to connect directly to the source.

Question 4

A company is deploying a new web application that uses Amazon RDS for MySQL. To meet high availability requirements, the database must automatically failover to a standby in a different Availability Zone with minimal downtime. Which deployment configuration should be used?

Accepted Answer

Multi-AZ deployment with automatic failover. A Multi-AZ deployment for Amazon RDS automatically provisions and maintains a synchronous standby replica in a different Availability Zone. If the primary DB instance fails, Amazon RDS automatically fails over to the standby, typically within 60–120 seconds, without requiring manual intervention. This meets the high availability requirement with minimal downtime.

Answer

Single-AZ deployment with enhanced monitoring

Answer

Multi-AZ cluster deployment

Answer

Single-AZ deployment with a read replica

Question 5

A company is migrating an on-premises MongoDB database to Amazon DocumentDB (with MongoDB compatibility). Which AWS service can perform the migration with minimal downtime using ongoing replication?

Accepted Answer

AWS Database Migration Service (AWS DMS). AWS DMS supports MongoDB as a source and Amazon DocumentDB as a target, enabling live migration with ongoing replication via change data capture (CDC). This allows the company to migrate with minimal downtime by continuously applying changes from the source MongoDB to the target DocumentDB until cutover.

Answer

Amazon CloudWatch

Answer

AWS Schema Conversion Tool (AWS SCT)

Answer

AWS Glue

Question 6

Which THREE factors should be considered when choosing between a native database migration tool (e.g., pg_dump) and AWS DMS for migrating a database to Amazon RDS? (Choose three.)

Accepted Answer

Downtime tolerance during migration. Option B (Downtime tolerance) is correct because native tools like pg_dump typically require the database to be taken offline or placed in read-only mode for a consistent dump, whereas AWS DMS supports continuous replication with minimal downtime, so the acceptable outage window directly drives the tool choice. Option C (Requirement for ongoing replication) is correct because AWS DMS provides Change Data Capture (CDC) via replication instances to keep source and target synchronized continuously, while pg_dump produces a point-in-time snapshot with no built-in ongoing sync capability. Option E (Total size and network bandwidth) is correct because large databases make native dump/restore slow and bandwidth-bound, while DMS uses parallel load and compression options that can be more efficient over constrained links. Option A is not a deciding factor because both native tools and DMS work across AWS regions; region placement affects latency and data transfer cost but not the fundamental tool selection. Option D is not a primary factor because complex transformations are handled by AWS SCT or ETL tools, not by DMS or pg_dump themselves, so it does not distinguish between these two migration approaches.

Answer

Whether the target database is in a different AWS region

Answer

Need to perform complex data transformations during migration

Question 7

Which TWO actions are recommended when deploying an Amazon RDS for MySQL instance in a production environment to ensure high availability and durability? (Choose two.)

Accepted Answer

Enable automated backups with a retention period of at least 7 days. Automated backups with a retention period of at least 7 days enable point-in-time recovery (PITR) within that window, which is critical for restoring a database to a specific second in the event of a failure or data corruption. This ensures durability by allowing you to recover from logical errors or accidental deletions, not just hardware failures. Option E is correct because Multi-AZ deployment automatically provisions and maintains a synchronous standby replica in a different Availability Zone, providing automatic failover for high availability without manual intervention.

Answer

Enable Enhanced Monitoring

Answer

Enable Performance Insights

Answer

Enable deletion protection

Question 8

A company has an Aurora MySQL cluster with three instances. The current writer instance is 'mycluster-instance-1'. The company wants to failover to 'mycluster-instance-2' for maintenance. What is the most direct way to achieve this?

Accepted Answer

Use the AWS CLI: aws rds failover-db-cluster --db-cluster-identifier mycluster --target-db-instance-identifier mycluster-instance-2. The AWS CLI command `aws rds failover-db-cluster` with the `--target-db-instance-identifier` parameter allows you to explicitly specify which Aurora replica should become the new writer instance. This is the most direct and supported method to initiate a controlled failover to 'mycluster-instance-2' without rebooting the current writer or manually modifying endpoints.

Answer

Change the cluster's endpoint to point to instance-2.

Answer

Modify 'mycluster-instance-2' to promote it to writer.

Answer

Reboot 'mycluster-instance-1' to trigger a failover.

Question 9

A company is migrating an on-premises PostgreSQL database to Amazon RDS for PostgreSQL. The database is 2 TB in size and has a sustained write rate of 50 MB/s. The migration must have minimal downtime. Which migration approach should be used?

Accepted Answer

Use AWS DMS with ongoing replication (change data capture). AWS DMS with ongoing replication (change data capture) is the correct approach because it allows a full load of the 2 TB database followed by continuous replication of changes from the on-premises PostgreSQL source to the RDS for PostgreSQL target, minimizing downtime to a brief cutover window. The sustained 50 MB/s write rate indicates a high-volume transactional workload that cannot be captured by a single full-load task, making CDC essential for near-zero downtime migration.

Answer

Create an RDS read replica from the on-premises database

Answer

Use pg_dump and pg_restore

Answer

Use AWS DMS with a full-load task only

Question 10

A company is deploying a new application that requires a highly available DynamoDB table with eventual consistency. The table will be accessed from multiple AWS Regions. What is the most appropriate deployment strategy?

Accepted Answer

Use DynamoDB global tables. DynamoDB global tables provide a fully managed, multi-Region, multi-active solution that automatically replicates data across selected AWS Regions, delivering eventual consistency and high availability for applications accessed from multiple Regions. This is the most appropriate strategy because it natively supports the requirement without custom code or additional infrastructure.

Answer

Use DynamoDB auto scaling to handle regional traffic

Answer

Use DynamoDB Accelerator (DAX) to cache data across regions

Answer

Use DynamoDB Streams to replicate data to another region

Question 11

A company is deploying a new application that uses Amazon RDS for PostgreSQL. The database must be highly available and fault-tolerant. Which deployment option meets these requirements?

Accepted Answer

Deploy the RDS instance with Multi-AZ configuration. Amazon RDS Multi-AZ deployment automatically provisions and maintains a synchronous standby replica in a different Availability Zone, providing automatic failover in the event of an AZ outage or primary instance failure. This configuration meets the requirements for high availability and fault tolerance by ensuring the database remains accessible with minimal downtime, as the standby replica is kept in sync synchronously and DNS is updated to point to the standby upon failover.

Answer

Deploy the RDS instance in a single Availability Zone

Answer

Deploy the RDS instance across multiple AWS Regions

Answer

Deploy the RDS instance with multiple read replicas

Question 12

Refer to the exhibit. A company is creating an Aurora MySQL cluster using the AWS CLI. The command fails with an error. The company has a default KMS key but the command specifies a customer-managed KMS key. What is the most likely cause of the failure?

Accepted Answer

The IAM user does not have permission to use the specified KMS key. The most likely cause of the failure is that the IAM user does not have the required permissions to use the specified customer-managed KMS key. When you specify a KMS key in the `--kms-key-id` parameter for an Aurora MySQL cluster, the IAM user must have `kms:CreateGrant`, `kms:Decrypt`, and `kms:Encrypt` permissions on that key. If the user lacks these permissions, the command fails even if the key exists and is in the correct region.

Answer

The --kms-key-id parameter is not supported for aurora-mysql engine

Answer

The KMS key does not exist

Answer

The KMS key is in a different region

Question 13

A company is migrating an on-premises MySQL database to Amazon RDS for MySQL. The database is 500 GB in size and has a 24-hour maintenance window. Which AWS service or tool should be used for the initial data transfer with minimal downtime?

Accepted Answer

AWS Database Migration Service (DMS). AWS Database Migration Service (DMS) is the correct choice because it supports ongoing replication from a source MySQL database to Amazon RDS for MySQL, allowing you to perform a full load followed by continuous change data capture (CDC) to minimize downtime. With a 500 GB database and a 24-hour maintenance window, DMS can complete the initial load and then keep the target in sync until you cut over, achieving near-zero downtime.

Answer

Amazon S3 with AWS Glue

Answer

AWS Snowball Edge

Answer

mysqldump and restore to RDS

Question 14

A financial services company is migrating a 10 TB Oracle data warehouse to Amazon Redshift. The source database uses a combination of partitioned tables, indexes, and materialized views. The migration team plans to use AWS SCT and DMS. Which approach should the team take to optimize query performance after migration?

Accepted Answer

Define appropriate distribution keys and sort keys. Amazon Redshift is a columnar data warehouse that does not support traditional indexes or the PARTITION BY clause used in Oracle. Instead, query performance in Redshift is optimized by defining appropriate distribution keys (to minimize data shuffling across nodes) and sort keys (to enable zone maps and reduce the amount of data scanned). This approach directly addresses the performance needs of the migrated 10 TB data warehouse.

Answer

Create indexes on frequently queried columns

Answer

Recreate all materialized views using standard views

Answer

Partition tables by date using the PARTITION BY clause

Question 15

A company is migrating a 2 TB Oracle database to Amazon Aurora PostgreSQL using AWS SCT and DMS. After migration, the application reports that some queries are significantly slower than before. The database schema was converted automatically. What is the most likely cause?

Accepted Answer

The schema conversion did not create appropriate indexes. The most likely cause is that AWS Schema Conversion Tool (SCT) converted the Oracle schema to Aurora PostgreSQL but did not automatically create optimal indexes. Oracle and PostgreSQL use different query optimizers and index strategies; SCT focuses on structural compatibility, not performance tuning. Without manual review and addition of appropriate indexes (e.g., for foreign keys, composite columns, or partial indexes), PostgreSQL may resort to sequential scans on large tables, causing significant query slowdowns.

Answer

Aurora storage is slower than Oracle's storage

Answer

DMS introduced data type conversions that slow down queries

Answer

Aurora PostgreSQL does not support partitioning, causing full table scans