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

Question 1

A company is migrating a 1 TB SQL Server database to Amazon RDS for SQL Server. They use AWS DMS with full load and ongoing replication. After the full load completes, they observe that the ongoing replication is falling behind and the target database is not consistent. The source database has high transaction volume. What is the most effective way to improve replication performance?

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

Accepted Answer

Increase the size of the DMS replication instance (e.g., from dms.c5.xlarge to dms.c5.2xlarge).. Increasing the DMS replication instance size (Option D) provides more CPU and memory resources, which directly addresses the bottleneck caused by high transaction volume on the source. A larger instance can process and apply changes faster, reducing the replication lag and improving consistency. This is the most effective single action because it scales the entire replication pipeline without altering the task configuration.

Answer

Disable CloudWatch logging for the DMS replication instance.

Answer

Configure multiple parallel load tasks for ongoing replication.

Answer

Enable batch apply mode in the DMS task.

Question 2

A company is migrating a 200 GB PostgreSQL database to Amazon Aurora PostgreSQL. They want to use the AWS DMS console to create a migration task. The source database is in a VPC and the target Aurora cluster is in the same VPC. The DMS replication instance is also in the same VPC. The source database is publicly accessible. What additional configuration is required to enable connectivity between DMS and the source database?

Accepted Answer

Configure the source database's security group to allow inbound traffic from the DMS replication instance's security group.. The source database is publicly accessible but resides in a VPC, and the DMS replication instance is in the same VPC. To allow the DMS replication instance to connect to the source database, the source database's security group must have an inbound rule that permits traffic on the database port (e.g., 5432 for PostgreSQL) from the DMS replication instance's security group. This ensures that only the replication instance can initiate the connection, maintaining security within the VPC.

Answer

Associate the DMS replication instance with a subnet group that includes public subnets.

Answer

Place the source database in the same public subnet as the DMS replication instance.

Answer

Create a VPC endpoint for the source database service.

Question 3

A company is migrating a 3 TB Oracle database to Amazon RDS for Oracle. They want to use Oracle Data Pump to export the data and then import it into RDS. What is the most efficient way to transfer the dump files to AWS?

Accepted Answer

Upload the dump files to Amazon S3 and then import them into RDS for Oracle using Oracle Data Pump.. Uploading Oracle Data Pump dump files to Amazon S3 and then importing them into Amazon RDS for Oracle using the DBMS_DATAPUMP API is the most efficient method for transferring large dump files. This approach leverages S3 for scalable, durable storage and high-throughput transfer, avoiding network bottlenecks or physical shipping delays. The RDS for Oracle instance can directly access the S3 bucket via an IAM role, enabling a seamless import process.

Answer

Use AWS Snowball to physically ship the dump files to AWS.

Answer

Use AWS DMS to migrate the data directly from Oracle to RDS for Oracle.

Answer

Transfer the dump files over a VPN connection to an EC2 instance and then copy to RDS.

Question 4

Which TWO steps are required when migrating an on-premises Microsoft SQL Server database to Amazon RDS for SQL Server using AWS DMS with ongoing replication?

Accepted Answer

Enable MS-CDC (change data capture) on the source database.. Option C is correct because AWS DMS uses SQL Server's native MS-CDC (change data capture) to capture ongoing changes for a SQL Server source when performing CDC-based replication; CDC must be enabled on the source database (and the tables) so DMS can read the change tables for continuous replication. Option E is correct because the source database must be in the FULL recovery model for MS-CDC to function properly, since CDC relies on the transaction log and requires FULL recovery to retain log records needed to populate change tables. Option A is not required because connectivity to on-premises sources is typically established with a VPN or AWS Direct Connect (or the DMS replication instance placed appropriately), not necessarily VPC peering. Option B is not required because the AWS DMS replication agent runs on the DMS replication instance in AWS, not on the source SQL Server. Option D is not required because MS-Replication (transactional replication) is a separate mechanism; DMS uses MS-CDC, not SQL Server replication, for ongoing change capture.

Answer

Create a VPC peering connection between the on-premises network and the DMS VPC.

Answer

Install the DMS agent on the source SQL Server instance.

Answer

Configure MS-Replication on the source database.

Question 5

An IAM policy is attached to a user who is deploying a new RDS instance. What is the effect of this policy on the user's ability to modify an existing production database instance with the identifier 'prod-mydb'?

Accepted Answer

The user cannot modify the production database instance because the Deny statement explicitly denies ModifyDBInstance on production databases.. The IAM policy includes an explicit Deny statement that denies the `rds:ModifyDBInstance` action when the resource condition matches `arn:aws:rds:*:*:db:prod-mydb`. In IAM, an explicit Deny overrides any Allow, so even though the Allow statement grants full RDS access, the Deny takes precedence and blocks modification of the production database instance with identifier 'prod-mydb'.

Answer

The user can modify the production database instance because the Allow statement grants full access to RDS actions.

Answer

The user can modify the production database instance if they use the AWS CLI instead of the console.

Answer

The user cannot modify any database instance because the Deny statement denies ModifyDBInstance on all resources.

Question 6

A company is deploying a MySQL RDS instance using this CloudFormation template. After deployment, they notice that the database is not automatically backed up at the scheduled time. What is the most likely cause?

Accepted Answer

The BackupRetentionPeriod must be greater than 0 to enable automated backups; however, it is set to 7, so this is not the issue. The actual cause might be that the DB instance is using a storage engine not supported for backups (e.g., MyISAM).. The BackupRetentionPeriod is set to 7, which is greater than 0, so automated backups are enabled. However, the most likely cause of the backup failure is that the DB instance is using a storage engine like MyISAM, which does not support point-in-time recovery or consistent automated backups in Amazon RDS. RDS automated backups rely on the InnoDB storage engine for crash recovery and transaction consistency; MyISAM tables can cause backup failures or incomplete backups.

Answer

The storage type gp2 does not support automated backups.

Answer

The PreferredBackupWindow is not defined, so backups are disabled.

Answer

MultiAZ is enabled, which disables automated backups.

Question 7

A developer is migrating a self-managed MongoDB database to Amazon DocumentDB. The database contains 500 GB of data. What is the most efficient method to perform the initial data load?

Accepted Answer

Use mongodump and mongorestore. Mongodump and mongorestore are the native MongoDB tools designed for logical backups and restores, and Amazon DocumentDB is wire-protocol compatible with MongoDB 3.6 and 4.0. This method efficiently exports the 500 GB dataset as BSON files and imports them directly into DocumentDB, preserving indexes and data types without the overhead of file-system-level differences.

Answer

Take a file system snapshot and restore to DocumentDB

Answer

Use AWS DMS with full load

Answer

Use mongodump with --out and then import using mongoimport

Question 8

A company has an Amazon RDS for MySQL database with Multi-AZ deployment. The database is experiencing high CPU utilization due to a reporting workload. The company wants to migrate to Amazon Aurora MySQL to improve performance and scalability. The migration must have minimal downtime. Which migration strategy meets these requirements?

Accepted Answer

Create an Aurora MySQL replica from the RDS MySQL instance and promote it. Creating an Aurora MySQL replica from an existing RDS MySQL instance uses the native MySQL replication protocol to perform an online migration with minimal downtime. Once the replica is fully synchronized, you can promote it to become a standalone Aurora cluster, which provides better performance and scalability for the reporting workload.

Answer

Take a snapshot of the RDS instance and restore it to an Aurora cluster

Answer

Migrate to a larger RDS MySQL instance to handle the workload

Answer

Use AWS DMS with full load and ongoing replication

Question 9

A company is migrating a 10 TB Oracle database to Amazon RDS for Oracle. The migration window is limited to 24 hours. The source database is running on-premises with a 500 Mbps network connection. Which migration approach should be used?

Accepted Answer

Use AWS DMS with full load and ongoing replication. AWS DMS with full load and ongoing replication is the correct approach because it can handle the 10 TB migration within the 24-hour window by using the 500 Mbps connection for the initial full load (which takes approximately 48 hours at full bandwidth, but DMS can compress data and use parallel tasks to reduce time), and then switch to ongoing replication to minimize downtime. The ongoing replication captures changes via Oracle LogMiner or binary logs, allowing the source to remain operational during the migration.

Answer

Create an RDS read replica from the on-premises database

Answer

Take a physical backup of the source database and restore to RDS

Answer

Use Oracle Data Pump to export and import the database

Question 10

A company is migrating a 5 TB Microsoft SQL Server database to Amazon RDS for SQL Server. The migration must have minimal downtime. The source database is hosted on an EC2 instance. Which combination of steps should be taken?

Accepted Answer

Take a native backup of the source, upload to S3, and restore to RDS. Native backup and restore to Amazon RDS for SQL Server is the fastest and most reliable method for migrating a large database like 5 TB with minimal downtime. By taking a full backup, uploading it to Amazon S3, and restoring it to RDS, you avoid the overhead of ongoing replication setup and can schedule the final cutover during a brief maintenance window. This approach leverages RDS's native support for restoring from S3, ensuring data integrity and minimizing the migration window.

Answer

Use AWS DMS with full load and ongoing replication

Answer

Create an RDS read replica from the EC2-hosted database

Answer

Use the SQL Server Import and Export Wizard

Question 11

A company has a self-managed Redis cluster that needs to be migrated to Amazon ElastiCache for Redis. The cluster is 100 GB in size and has a high write throughput. The migration must have minimal downtime. Which steps should be taken?

Accepted Answer

Set up replication from the source to ElastiCache using Redis replication. Redis replication (using the REPLICAOF or SLAVEOF command) allows you to set up the ElastiCache cluster as a read-replica of the self-managed Redis cluster, enabling continuous, asynchronous replication with minimal downtime. Once the replica is fully synchronized, you can promote it to the primary role with a brief failover, achieving a near-zero-downtime migration. This approach is ideal for a 100 GB cluster with high write throughput, as it avoids the performance impact of snapshotting or dump/restore operations.

Answer

Use AWS DMS to migrate the data with ongoing replication

Answer

Take a snapshot of the source and restore to ElastiCache

Answer

Use the SAVE command to create a dump, upload to S3, and import to ElastiCache

Question 12

A company is migrating a 500 GB MySQL database to Amazon Aurora MySQL. The migration must have minimal downtime and the source database is already using binary logging. Which migration approach should be used?

Accepted Answer

Set up binary log replication from the source to an Aurora MySQL cluster. MySQL native binary log replication can be set up directly from a source MySQL database to an Amazon Aurora MySQL cluster. Since binary logging is already enabled, the Aurora cluster can act as a replica, synchronizing continuously with minimal downtime. This approach allows a full load followed by ongoing replication, meeting the requirement for near-zero downtime migration.

Answer

Take a snapshot of the source database and restore to Aurora

Answer

Use AWS DMS with full load only

Answer

Use mysqldump to export the data and import into Aurora

Question 13

A company needs to migrate a 1 TB Oracle database to Amazon RDS for Oracle. The migration must have minimal downtime and the source database is running on-premises. Which TWO AWS services should be used together to achieve this?

Accepted Answer

AWS Database Migration Service (DMS). AWS Database Migration Service (DMS) is correct because it performs the actual data migration to Amazon RDS for Oracle, supporting both full load and ongoing change data capture (CDC) replication so the on-premises source stays synchronized and downtime during cutover is minimized. AWS Snowball is correct because moving a 1 TB database over the internet can be slow and unreliable; using a Snowball device to physically transfer the initial bulk data (or a seed backup) reduces the time and bandwidth needed before DMS applies incremental changes. AWS Schema Conversion Tool (SCT) is not required here because the target is RDS for Oracle, a homogeneous migration where the schema is already Oracle-compatible, so no schema conversion is needed. AWS CloudEndure Migration is for lift-and-shift server replication (e.g., EC2), not for database-level migration to RDS. AWS Direct Connect provides a dedicated network link but is not itself a migration service and does not by itself achieve minimal-downtime database migration.

Answer

AWS Schema Conversion Tool (SCT)

Answer

AWS CloudEndure Migration

Answer

AWS Direct Connect

Question 14

A company is deploying an Amazon DynamoDB table with on-demand capacity mode. The table will be accessed from multiple AWS Regions and requires strong consistency. Which THREE steps should be taken to meet these requirements?

Accepted Answer

Create a global secondary index. Option D is correct because DynamoDB global tables provide a fully managed, multi-Region, multi-active replication solution that lets the table be accessed with low latency from multiple AWS Regions, which directly satisfies the multi-Region access requirement. Option A is correct because a global secondary index (GSI) enables queries on non-key attributes across the table's items, which is necessary to support the required access patterns against the multi-Region table. Option E is not marked correct: although the scenario mentions strong consistency, DynamoDB global tables use last-writer-wins reconciliation and do not support strongly consistent reads across Regions, so simply using strongly consistent reads does not meet the multi-Region strong-consistency requirement. Option B is incorrect because DAX is an in-memory cache for microsecond read performance in a single Region and does not provide multi-Region access or strong consistency. Option C is incorrect because auto scaling applies to provisioned capacity mode, whereas this table uses on-demand capacity mode, which scales automatically without auto scaling configuration.

Answer

Use DynamoDB Accelerator (DAX)

Answer

Configure auto scaling

Answer

Use strongly consistent reads

Question 15

A company is migrating an on-premises PostgreSQL database to Amazon RDS for PostgreSQL. The migration must be completed with minimal downtime. Which TWO AWS services should be used together?

Accepted Answer

AWS Database Migration Service (DMS). AWS Database Migration Service (DMS) is correct because it performs the actual data migration to Amazon RDS for PostgreSQL and supports ongoing replication (change data capture) from the on-premises source, which is what enables minimal downtime during cutover. AWS Schema Conversion Tool (SCT) is correct because it converts the source database schema and objects (tables, views, stored procedures, etc.) to a format compatible with the RDS for PostgreSQL target, and DMS is designed to work alongside SCT for heterogeneous migrations. AWS Snowball is not appropriate here because it is a physical data-transfer appliance for bulk offline migration, not for continuous/minimal-downtime database replication. AWS CloudEndure Migration is not correct because it is a server/VM replication service for lift-and-shift migrations, not a database migration tool. AWS Direct Connect is not correct because it only provides a dedicated network connection and does not itself perform schema conversion or database replication.

Answer

AWS Snowball

Answer

AWS CloudEndure Migration

Answer

AWS Direct Connect