DBS-C01 Deployment and Migration Practice Test 16 — 15 Questions

Question 1

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?

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

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

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Multi-AZ cluster deployment

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Single-AZ deployment with a read replica

Question 2

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?

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.

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Configure multiple parallel load tasks for ongoing replication.

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Enable batch apply mode in the DMS task.

Question 3

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.

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Amazon CloudWatch

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AWS Schema Conversion Tool (AWS SCT)

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AWS Glue

Question 4

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.

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

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Create a VPC endpoint for the source database service.

Question 5

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.

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

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

Question 6

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.. AWS DMS requires MS-CDC (change data capture) to be enabled on the source SQL Server database when using ongoing replication (change data capture). CDC captures insert, update, and delete activity from the transaction log, allowing DMS to apply those changes to the target RDS for SQL Server instance without requiring full table reloads.

Answer

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

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Install the DMS agent on the source SQL Server instance.

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Configure MS-Replication on the source database.

Question 7

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. Downtime tolerance directly influences the choice between a one-time logical dump (pg_dump) and AWS DMS, which supports minimal-downtime migrations via ongoing replication. pg_dump requires the source database to be read-consistent during the dump, often necessitating a read-only or quiesced state, whereas DMS can perform a full load followed by continuous change data capture (CDC) to keep the target nearly in sync with minimal application downtime.

Answer

Whether the target database is in a different AWS region

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Need to perform complex data transformations during migration

Question 8

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

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Enable Performance Insights

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Enable deletion protection

Question 9

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.

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

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

Question 10

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.

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

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

Question 11

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.

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The PreferredBackupWindow is not defined, so backups are disabled.

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MultiAZ is enabled, which disables automated backups.

Question 12

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 13

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 14

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 15

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

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

Answer

Use Oracle Data Pump to export and import the database