DBS-C01 Deployment and Migration Practice Test 8 — 15 Questions

Question 1

A company is migrating a 2 TB SQL Server database to Amazon RDS for SQL Server. They have a limited maintenance window and need to minimize downtime. Which TWO strategies should they combine?

Accepted Answer

Use AWS DMS to perform a full load and ongoing replication.. AWS DMS (Database Migration Service) is correct because it can perform a full load of the 2 TB SQL Server database to Amazon RDS for SQL Server, then continuously replicate ongoing changes using change data capture (CDC). This minimizes downtime by allowing the source database to remain operational during migration, and the target can be synchronized with minimal interruption before cutover.

Answer

Use AWS Direct Connect to increase bandwidth.

Answer

Use AWS CloudEndure Migration.

Answer

Use AWS Snowball to transfer a backup offline.

Question 2

A company is deploying an Amazon Aurora MySQL database with read replicas. They need to ensure high availability and disaster recovery across AWS Regions. Which THREE components should be included?

Accepted Answer

Aurora Replicas in the same Region. Aurora Replicas in the same Region provide read scaling and automatic failover within an AWS Region. They share the same underlying storage volume as the primary instance, so failover is fast (typically under 30 seconds) and does not require data rehydration. This is a core component for high availability within a single Region.

Answer

Auto Scaling groups

Answer

Amazon CloudFront

Question 3

A company is migrating a 500 GB Oracle database to Amazon Aurora PostgreSQL. Which THREE steps should be part of the migration plan?

Accepted Answer

Use AWS DMS to perform a full load and ongoing replication from Oracle to Aurora.. AWS DMS supports heterogeneous migrations from Oracle to Aurora PostgreSQL, performing a full load followed by ongoing change data capture (CDC) using Oracle's redo logs to replicate changes with minimal downtime. This makes it the correct service for both the initial data transfer and continuous replication during migration.

Answer

Use AWS Snowball to transfer the database files.

Answer

Set up AWS Direct Connect between on-premises and AWS.

Question 4

Refer to the exhibit. A developer wants to connect to the database. Which database engine is most likely being used?

Accepted Answer

MySQL. The exhibit shows a connection string using the format `jdbc:mysql://...`, which is the standard JDBC URL prefix for MySQL databases. This indicates the developer is connecting to a MySQL database engine, as Oracle, SQL Server, and PostgreSQL use different JDBC URL prefixes (`jdbc:oracle:thin:`, `jdbc:sqlserver://`, and `jdbc:postgresql://` respectively).

Answer

Oracle

Answer

SQL Server

Answer

PostgreSQL

Question 5

Refer to the exhibit. An IAM policy is attached to a user. The user attempts to create an RDS DB instance named 'new-prod-db' with Oracle Standard Edition Two engine. What will happen?

Accepted Answer

The request will fail because the Deny condition matches the engine.. The IAM policy includes an explicit Deny for the `rds:CreateDBInstance` action when the engine is `oracle-se2`, which matches the Oracle Standard Edition Two engine. Since explicit Deny statements override any Allow statements, the request fails regardless of the name pattern match. AWS IAM evaluates Deny statements first, making the Deny effective and blocking the operation.

Answer

The request will fail because there is no Allow for 'new-prod-db'.

Answer

The request will succeed because the Allow matches the name pattern.

Answer

The request will succeed because the Deny is not effective for 'new-prod-db'.

Question 6

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

Accepted Answer

AWS DMS. AWS DMS (Database Migration Service) is the correct choice because it supports both full-load migration and ongoing change data capture (CDC) replication from an on-premises PostgreSQL source to Amazon RDS for PostgreSQL, enabling minimal downtime. DMS uses logical replication slots to capture incremental changes, allowing the target database to stay synchronized during the cutover window.

Answer

AWS Snowball Edge

Answer

AWS S3

Answer

RDS native PostgreSQL logical replication

Question 7

A company wants to migrate a 500 GB SQL Server database to Amazon RDS for SQL Server with the least amount of downtime. The on-premises network has a 1 Gbps connection to AWS. Which approach should be used?

Accepted Answer

Use AWS DMS with ongoing replication from on-premises to RDS. AWS DMS with ongoing replication (change data capture, CDC) allows you to perform a full load of the 500 GB database while continuously replicating ongoing changes from the on-premises SQL Server to Amazon RDS for SQL Server. This minimizes downtime to a brief cutover window when you stop writes on the source and redirect traffic to the target. The 1 Gbps connection is sufficient for the initial load and ongoing replication, making this the most effective approach for minimal downtime.

Answer

Use AWS Snowball to transfer the database backup, then restore to RDS

Answer

Copy database files to S3 and then use RDS import

Answer

Use native SQL Server backup to S3, then restore to RDS

Question 8

A company is migrating a 4 TB Oracle database to Amazon Aurora PostgreSQL using AWS DMS. The migration completes successfully but the application experiences high latency on the Aurora cluster. The DMS task used LOB mode 'full LOB mode'. What is the most likely cause of the latency?

Accepted Answer

Full LOB mode caused large LOBs to be stored in the Aurora cluster, leading to increased I/O. Full LOB mode in AWS DMS loads entire LOBs into memory before writing them to the target, which can cause large LOBs to be stored in the Aurora cluster. This increases I/O and storage overhead, leading to high latency on the Aurora cluster, especially if the LOBs are significantly larger than the default chunk size or if the cluster's I/O capacity is exceeded.

Answer

The Aurora cluster was underprovisioned for parallel load

Answer

The DMS task was configured with 'ongoing replication' causing continuous write load

Answer

The DMS task replicated data to a different region, causing network latency

Question 9

A company is migrating an on-premises MongoDB database to Amazon DocumentDB. The migration must be online with minimal downtime. Which AWS service should be used?

Accepted Answer

AWS DMS. AWS Database Migration Service (DMS) is the correct choice because it supports ongoing replication (change data capture) from MongoDB to Amazon DocumentDB, enabling an online migration with minimal downtime. DMS can perform a full load of existing data and then continuously replicate changes from the source MongoDB oplog to keep the target DocumentDB synchronized until cutover.

Answer

AWS DataSync

Answer

AWS S3

Answer

AWS Snowball Edge

Question 10

A company uses a self-hosted MySQL database on EC2. They want to migrate to Amazon RDS for MySQL with minimal downtime and automated failover. Which migration strategy should be used?

Accepted Answer

Set up MySQL replication from EC2 to RDS, then cut over. Setting up MySQL native replication from the EC2-hosted MySQL database to an Amazon RDS for MySQL instance allows for near-zero downtime migration. Once replication is established and lag is minimal, you can simply stop writes on the source, verify replication has caught up, and redirect traffic to the RDS endpoint. This approach also supports automated failover by enabling Multi-AZ on the RDS instance, which provides a synchronous standby replica in a different Availability Zone.

Answer

Use mysqldump to export the database and import to RDS

Answer

Take a snapshot of the EC2 instance and restore to RDS

Answer

Use AWS DMS with full load and CDC

Question 11

A company is migrating a 10 TB Oracle database to Amazon Aurora PostgreSQL. The migration uses AWS DMS with CDC. After the full load, the CDC phase is falling behind by several minutes. The source Oracle database generates 500 MB of redo logs per minute. Which action will most likely improve CDC performance?

Accepted Answer

Increase the number of parallel apply threads on the DMS task. Increasing the number of parallel apply threads on the DMS task allows the target Aurora PostgreSQL database to apply changes concurrently, reducing the bottleneck caused by sequential apply. With 500 MB/min of redo logs, the single-threaded default apply cannot keep pace, so parallel apply directly addresses the lag by distributing the load across multiple threads.

Answer

Disable CDC and perform a full load only

Answer

Reduce the batch size in the DMS task settings

Answer

Increase the source Oracle redo log size

Question 12

A company needs to migrate a 100 GB on-premises SQL Server database to Amazon RDS for SQL Server. The migration must be completed within a 4-hour maintenance window. The network link has 500 Mbps throughput. Which approach should be used?

Accepted Answer

Use native SQL Server backup to S3, then restore to RDS. Native SQL Server backup to S3 and restore to RDS is the fastest method for a 100 GB database over a 500 Mbps link. At 500 Mbps, the theoretical transfer time for 100 GB is approximately 28 minutes (100 GB * 8 / 500 Mbps), well within the 4-hour window, making Snowball unnecessary. This approach avoids the overhead of change data capture (CDC) and additional compute resources, directly leveraging SQL Server's native backup/restore capabilities.

Answer

Use AWS DMS with full load and CDC

Answer

Use AWS Snowball Edge to transfer the backup

Answer

Launch an EC2 instance with SQL Server, copy the database, and then migrate to RDS

Question 13

A company has a 200 GB PostgreSQL database on-premises and wants to migrate to Amazon RDS for PostgreSQL. The company requires encrypted data transfer and wants to minimize downtime. Which combination of services should be used?

Accepted Answer

Use AWS DMS with SSL and ongoing replication. AWS DMS with SSL provides encrypted data transfer and supports ongoing replication (change data capture) to minimize downtime. This allows the on-premises PostgreSQL database to remain operational during the initial full load and then continuously replicate changes until cutover, meeting both security and minimal-downtime requirements.

Answer

Use native pg_dump to S3, then import to RDS

Answer

Use AWS VPN to connect on-premises to RDS and perform a database dump

Answer

Use an EC2 instance with PostgreSQL replication to RDS

Question 14

A company is migrating a 5 TB Oracle database to Amazon Aurora MySQL using AWS DMS. The full load completes successfully, but the CDC phase is slow and the target Aurora cluster is consuming high CPU. The DMS instance type is dms.c4.2xlarge. Which change will most likely improve CDC performance?

Accepted Answer

Increase the number of parallel apply threads in the DMS task. Increasing the number of parallel apply threads in the DMS task allows the CDC phase to apply multiple transactions concurrently to the target Aurora cluster, reducing the backlog of changes. The high CPU on the target suggests the apply process is the bottleneck, not the source or network, and DMS's parallel apply threads directly address this by enabling multi-threaded writes, which improves throughput without requiring larger instances.

Answer

Increase the Aurora cluster's max_connections parameter

Answer

Increase the DMS task's target storage allocation

Answer

Change the Aurora cluster to a larger instance class

Question 15

Which TWO factors should be considered when selecting a migration method from on-premises Oracle to Amazon RDS for Oracle?

Accepted Answer

The size of the database and available network bandwidth. The size of the database directly impacts the time required for data transfer, and available network bandwidth determines the maximum throughput for that transfer. For large databases over limited bandwidth, full offline migration may be impractical, requiring incremental or online methods like AWS DMS with ongoing replication to minimize transfer time.

Answer

The version of the Oracle client used by applications

Answer

The number of stored procedures in the database

Answer

The number of indexes on the source database