DBS-C01 Deployment and Migration — 100 Questions

Question 1

A company is migrating an on-premises Microsoft SQL Server database to Amazon RDS for SQL Server. The database uses SQL Server Agent jobs for ETL processes. After migration, the company needs to continue running these jobs. What is the MOST efficient way to manage these jobs in the AWS cloud?

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

Accepted Answer

Recreate the jobs as AWS Lambda functions and trigger them with Amazon CloudWatch Events.. AWS Lambda functions triggered by Amazon CloudWatch Events (now Amazon EventBridge) provide a serverless, fully managed alternative to SQL Server Agent jobs. This approach eliminates the need to manage any compute infrastructure, as Lambda handles the execution of ETL logic directly against the RDS for SQL Server instance. It is the most efficient because it requires no additional servers, reduces operational overhead, and integrates natively with AWS monitoring and scheduling services.

Answer

Install SQL Server Agent on an Amazon EC2 instance and connect to RDS.

Answer

Use the AWS Schema Conversion Tool (AWS SCT) to convert the jobs to PostgreSQL functions.

Answer

Use AWS Database Migration Service (AWS DMS) tasks to replicate the jobs.

Question 2

A company is deploying a new Amazon RDS for PostgreSQL database. The database will be used by an application that requires read-after-write consistency and low latency. Which deployment configuration is MOST suitable?

Accepted Answer

Deploy as a single-AZ instance with increased instance size. Read replicas in RDS for PostgreSQL use asynchronous replication and do not guarantee read-after-write consistency. For an application requiring read-after-write consistency and low latency, the best choice is to deploy as a single-AZ instance with increased instance size. This avoids replication lag entirely, ensuring that reads from the primary instance always reflect the latest writes, while scaling up provides low latency for both reads and writes.

Answer

Deploy with one or more read replicas in the same region

Answer

Deploy with cross-region replicas

Answer

Deploy as Multi-AZ with a synchronous standby

Question 3

A company is migrating a 2 TB MySQL database to Amazon Aurora MySQL. They need to minimize downtime and ensure data consistency. Which TWO actions should they take? (Choose two.)

Accepted Answer

Create an Amazon Aurora MySQL read replica from an Amazon RDS MySQL DB instance.. Both Option C and Option E are correct. Option C: Creating an Amazon Aurora MySQL read replica from an existing Amazon RDS MySQL DB instance uses MySQL native replication. The Aurora replica stays synchronized with minimal performance impact. When the replica lag reaches zero, you can promote the Aurora instance to a standalone primary, resulting in very low downtime and full data consistency. Option E: Enabling binary logging (binlog) on the source RDS MySQL instance and setting up replication to Aurora MySQL (for example, by creating an Aurora read replica or configuring an external replication channel) ensures continuous synchronization. This method also minimizes downtime and maintains data consistency. Both approaches avoid the need for a full export/import and are ideal for large databases like 2 TB. Options A (mysqldump) would require a long maintenance window, Option B (SCT) handles schema conversion only, and Option D (DMS with CDC) is a valid migration tool but is not the preferred approach here because native replication is simpler and more efficient for MySQL-to-Aurora MySQL migrations.

Answer

Export data using mysqldump and import into Aurora during a maintenance window.

Answer

Use AWS Schema Conversion Tool (SCT) to convert the schema to Aurora MySQL.

Answer

Use AWS Database Migration Service (DMS) with change data capture (CDC) to migrate data.

Question 4

A developer deploys the CloudFormation stack. After testing, they delete the stack. What happens to the RDS instance?

Accepted Answer

The RDS instance is deleted after a final snapshot is taken.. By default, when a CloudFormation stack containing an RDS DB instance is deleted, the instance is deleted and a final snapshot is taken automatically (unless the SkipFinalSnapshot property is explicitly set to true). The stem does not mention any custom DeletionPolicy or DeletionProtection, so the default behavior applies. Option B correctly describes this outcome.

Answer

The RDS instance is retained and the stack deletion fails.

Answer

The RDS instance is deleted without a final snapshot.

Answer

The RDS instance is retained and a final snapshot is taken automatically.

Question 5

A company is migrating an on-premises MySQL database to Amazon RDS for MySQL. Which TWO AWS services can assist in assessing the source database for compatibility issues?

Accepted Answer

AWS Database Migration Service (DMS). AWS DMS and AWS Schema Conversion Tool (SCT) are both used to assess source MySQL databases for compatibility when migrating to Amazon RDS for MySQL. AWS DMS provides a premigration assessment that checks for unsupported data types, table storage engines, and other potential blockers. AWS SCT helps identify schema incompatibilities and can automatically convert the database schema to match the target RDS for MySQL environment. Together, they help identify issues before migration begins, reducing the risk of failures.

Answer

AWS Trusted Advisor

Answer

Amazon CloudWatch

Answer

Amazon Inspector

Question 6

A company is migrating a self-hosted MongoDB replica set to Amazon DocumentDB. The source MongoDB is version 4.0, and the target DocumentDB is 3.6. The migration must be online with minimal downtime. Which approach should be taken?

Accepted Answer

Use AWS DMS with ongoing replication from MongoDB to DocumentDB.. AWS DMS supports ongoing replication (change data capture) from MongoDB to Amazon DocumentDB. It can capture changes from the MongoDB oplog and apply them to DocumentDB in near real-time, enabling an online migration with minimal downtime. Option B is incorrect because using a custom application to capture oplog changes is unnecessary and more complex, as DMS provides built-in CDC functionality for this migration path.

Answer

Use a custom application to capture MongoDB oplog changes and apply to DocumentDB.

Answer

Configure DocumentDB as a replica of the MongoDB primary.

Answer

Export MongoDB collection data to JSON files, then import into DocumentDB.

Question 7

A company is migrating a 3 TB SQL Server database to Amazon RDS for SQL Server. The migration must have minimal downtime. The current database uses Transparent Data Encryption (TDE). Which TWO steps are necessary to complete the migration? (Choose two.)

Accepted Answer

Export the TDE certificate and private key from the source and import them to the target RDS instance.. TDE-encrypted databases require the certificate and private key to be exported from the source and imported into the target RDS instance; otherwise, the restored database will be inaccessible. Option C is correct because native SQL Server backup and restore to S3 is the recommended approach for large databases to minimize downtime: the backup is taken while the source is online, copied to S3, and restored onto RDS, followed by CDC replication for ongoing changes. Option A is incorrect because the simple recovery model does not support CDC and would prevent log backups. Option D is incorrect because the target is SQL Server, not Aurora, so schema conversion is unnecessary. Option E is incorrect because full supplemental logging is an Oracle concept; for SQL Server, CDC requires enabling Change Data Capture and setting the recovery model to full, not enabling full supplemental logging.

Answer

Set the source database recovery model to simple to reduce log size.

Answer

Use AWS SCT to convert the schema to Amazon Aurora.

Answer

Enable full supplemental logging on the source database for DMS CDC.

Question 8

A company is migrating a 3 TB SQL Server database to Amazon RDS for SQL Server. They have limited network bandwidth (100 Mbps) and need to complete the migration within 3 days. Which two approaches could meet the requirements? (Choose TWO.)

Accepted Answer

Use AWS Snowball to physically transfer a full database backup to AWS, then restore into RDS.. AWS Snowball provides a physical appliance that can transfer the 3 TB database backup offline, bypassing the 100 Mbps bandwidth limitation entirely. The full backup can be restored into RDS for SQL Server using the native restore process, making it feasible within the 3-day window. Option D is correct because AWS DMS with ongoing replication can perform the initial full load over the internet; at 100 Mbps, the full load of 3 TB takes approximately 2.78 days, which is within the 3-day window. Ongoing replication then captures changes until cutover, ensuring data consistency and minimal downtime.

Answer

Export the database to a flat file, compress it, and upload to S3 via the internet, then import into RDS.

Answer

Use AWS DataSync to transfer the database files directly to Amazon S3.

Answer

Establish a VPN connection and use AWS DMS with full load only.

Question 9

A company is migrating a 500 GB SQL Server database to Amazon RDS for SQL Server. They need to minimize downtime. Which TWO actions should they take? (Choose two.)

Accepted Answer

Use AWS DMS with ongoing change data capture (CDC). AWS DMS with ongoing change data capture (CDC) minimizes downtime by performing a full load of the 500 GB database and then continuously replicating ongoing changes from the source SQL Server to the target Amazon RDS for SQL Server. This keeps the target nearly synchronized, so the final cutover can be completed in seconds or minutes. Setting up AWS Direct Connect provides a dedicated, high-bandwidth network connection between the on-premises environment and AWS, which reduces latency and increases transfer speed for the initial load and ongoing replication, further minimizing downtime. Together, these two actions effectively reduce overall downtime during the migration.

Answer

Store database backup files in Amazon S3

Answer

Use AWS Schema Conversion Tool to convert the schema

Answer

After migration, enable Multi-AZ for high availability

Question 10

A company needs to migrate a 5 TB Oracle database to Amazon Aurora PostgreSQL. The company has a limited maintenance window and requires the migration to be completed within a few hours. Which approach should be used?

Accepted Answer

Use AWS Database Migration Service (AWS DMS) to migrate the data. AWS Database Migration Service (AWS DMS) can migrate data directly from Oracle to Aurora PostgreSQL, including both schema conversion and data migration. DMS supports automatic schema conversion for many source/target pairs, including Oracle to PostgreSQL, so a separate schema conversion tool like AWS SCT is not required. With parallel load and change data capture (CDC), DMS can complete a 5 TB migration within a few hours while minimizing downtime.

Answer

Use AWS Schema Conversion Tool (AWS SCT) to convert the schema and AWS DMS for data migration

Answer

Use pg_dump to export the Oracle database and pg_restore to import into Aurora

Answer

Use AWS S3 to store the data and AWS Glue to transform and load into Aurora

Question 11

A company is migrating a 1 TB PostgreSQL database from on-premises to Amazon RDS for PostgreSQL. The migration must have minimal downtime. Which TWO steps should be taken to achieve this?

Accepted Answer

Configure AWS DMS with ongoing replication from the source to the target.. AWS DMS with ongoing replication (change data capture, CDC) allows continuous synchronization from the on-premises PostgreSQL source to the RDS target, enabling a cutover with minimal downtime. DMS captures incremental changes using PostgreSQL's logical replication slots, so only a brief outage is needed to stop writes and finalize the migration. Similarly, the pglogical extension provides logical replication directly from on-premises PostgreSQL to RDS for PostgreSQL, also enabling continuous syncing and minimal downtime. Both options A and C achieve the goal of minimal downtime by allowing a full load plus ongoing replication.

Answer

Use AWS SCT to convert the schema to Amazon Aurora.

Answer

Take a full backup using pg_dump and import it into RDS during a maintenance window.

Answer

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

Question 12

A company is migrating a 2 TB on-premises Microsoft SQL Server database to Amazon RDS for SQL Server. The migration must have minimal downtime. The company uses AWS DMS with ongoing CDC. During the full load phase, the DMS task fails with an error indicating that the source table 'Orders' has a large number of LOB columns and the task is running out of memory. The DMS replication instance is a dms.c4.large with 4 GB RAM. The company needs to complete the migration successfully. What should the company do?

Accepted Answer

Increase the replication instance size to dms.c4.xlarge (8 GB RAM).. Increasing the replication instance size provides more memory to handle LOB columns during the full load phase. Option A is incorrect because setting the LOB chunk size to 64 KB may reduce memory consumption per LOB but might not be sufficient to resolve the out-of-memory error; increasing instance size is a more direct solution. Option C is incorrect because splitting the table into multiple tasks does not address the underlying memory constraint; it could even increase memory usage due to multiple tasks running simultaneously. Option D is incorrect because disabling LOB support would truncate LOB data, leading to data loss.

Answer

Set the LOB chunk size to 64 KB in the task settings.

Answer

Split the 'Orders' table into multiple DMS tasks running in parallel.

Answer

Change the DMS task settings to disable LOB support for the 'Orders' table.

Question 13

A company is migrating an on-premises PostgreSQL database to Amazon RDS for PostgreSQL. The database is 2 TB in size and has a high write workload. The company needs to minimize downtime during the migration. Which AWS service or feature should the company use to achieve this?

Accepted Answer

Use AWS Database Migration Service (AWS DMS) with ongoing replication.. AWS DMS with ongoing replication (change data capture, CDC) is the correct choice because it allows continuous synchronization of the source PostgreSQL database with the target RDS for PostgreSQL instance after an initial full load. This minimizes downtime by enabling the target to stay up-to-date with changes until the cutover, which is critical for a 2 TB database with a high write workload.

Answer

Use pg_dump and pg_restore to export and import the database.

Answer

Use the AWS Schema Conversion Tool (AWS SCT) to convert the schema and migrate data.

Answer

Use AWS DataSync to replicate the database files.

Question 14

A company wants to migrate its on-premises Oracle database to Amazon Aurora PostgreSQL. The company needs to automatically convert the Oracle schema to PostgreSQL-compatible format. Which AWS service should the company use?

Accepted Answer

AWS Schema Conversion Tool (AWS SCT). AWS Schema Conversion Tool (AWS SCT) is designed specifically to convert database schemas from one engine to another, including Oracle to Amazon Aurora PostgreSQL. It automatically translates Oracle DDL (tables, indexes, stored procedures, functions, etc.) into PostgreSQL-compatible format, handling data type mappings, PL/SQL to PL/pgSQL conversion, and other schema-level transformations. AWS DMS handles data migration, not schema conversion, making SCT the correct choice for this requirement.

Answer

AWS Database Migration Service (AWS DMS) with the Oracle native dump and load option

Answer

AWS Server Migration Service (AWS SMS)

Answer

AWS Database Migration Service (AWS DMS)

Question 15

A company is using AWS Database Migration Service (AWS DMS) to migrate a 5 TB MySQL database to Amazon RDS for MySQL. The migration is taking longer than expected. The company notices that the source database has a high volume of write operations. Which configuration change would MOST likely improve the migration performance?

Accepted Answer

Increase the number of parallel threads in the DMS task settings.. Increasing the number of parallel threads in the DMS task settings allows AWS DMS to process multiple table partitions or row changes concurrently, which directly addresses the bottleneck caused by a high volume of write operations on the source. By default, DMS uses a single thread per table, but when the source is under heavy write load, parallel threads can capture and apply changes more efficiently, reducing the overall migration time.

Answer

Enable Multi-AZ on the target RDS instance.

Answer

Use a smaller instance class for the replication instance to reduce cost.

Answer

Set the LOB mode to 'Full LOB mode'.

Question 16

A company needs to migrate a 100 GB MongoDB database to Amazon DocumentDB (with MongoDB compatibility). The migration must have minimal impact on the source database performance. Which approach should the company take?

Accepted Answer

Use AWS Database Migration Service (AWS DMS) with ongoing replication from the MongoDB source.. AWS DMS with ongoing replication is the correct approach because it supports continuous change data capture (CDC) from MongoDB, enabling a live migration with minimal performance impact on the source. DMS reads the MongoDB oplog to capture changes without locking the database, which is critical for a 100 GB production database. This allows the target DocumentDB to stay synchronized until cutover, reducing downtime and avoiding the need for a full export/import that would strain the source.

Answer

Use AWS DataSync to transfer the MongoDB data files.

Answer

Set up a MongoDB replica set on Amazon EC2 and promote it to primary, then migrate to DocumentDB.

Answer

Use mongodump to export the data and mongorestore to import into DocumentDB.

Question 17

A company is migrating a 3 TB on-premises Oracle database to Amazon Aurora PostgreSQL using AWS DMS. The migration task is failing with an error indicating insufficient memory. Which TWO actions should the company take to resolve this issue? (Choose TWO.)

Accepted Answer

Increase the instance class of the DMS replication instance.. The 'insufficient memory' error during an AWS DMS migration indicates that the replication instance lacks the memory required to handle the data volume, transformation rules, or cache for large transactions. Increasing the instance class (e.g., from dms.c5.large to dms.c5.2xlarge) provides more memory and CPU, directly resolving the resource constraint.

Answer

Change the target database engine to Amazon RDS for MySQL.

Answer

Disable Multi-AZ on the DMS replication instance.

Answer

Use a smaller instance class for the DMS replication instance.

Question 18

A company is planning to migrate a 1 TB MySQL database from on-premises to Amazon RDS for MySQL. The migration must have minimal downtime and support ongoing replication. Which THREE steps should the company include in the migration plan? (Choose THREE.)

Accepted Answer

Set up an AWS Direct Connect or VPN connection between on-premises and AWS.. A stable, low-latency network connection (Direct Connect or VPN) is essential for AWS DMS to perform ongoing replication with minimal downtime. Without this, the replication can be interrupted by network issues, causing data loss or extended cutover windows.

Answer

Deploy an Amazon EC2 instance to act as a proxy for the DMS replication.

Answer

Install the AWS Schema Conversion Tool on the source server to convert the schema.

Question 19

A team is setting up a DMS migration task. The IAM policy above is attached to the DMS replication instance's IAM role. The team is unable to modify the target RDS instance's maintenance window during the migration. Which additional permission is missing?

Accepted Answer

Add 'rds:ModifyDBInstance' permission for the target RDS instance.. Modifying the target RDS instance's maintenance window requires the `rds:ModifyDBInstance` permission. The DMS replication instance's IAM role must have this permission for the target RDS instance to allow the migration task to adjust the maintenance window, which is necessary to prevent conflicts during ongoing replication. Without this permission, the DMS task cannot alter the maintenance window, even if the IAM role has other RDS permissions.

Answer

Add 'rds:ModifyOptionGroup' permission for the target RDS instance.

Answer

Add 'dms:ModifyReplicationInstance' permission for the DMS replication instance.

Answer

Add 'ec2:DescribeVpcs' permission to the policy.

Question 20

A team is migrating an on-premises database to Amazon RDS using AWS DMS. After the full load completed, the task stopped. The team needs to perform ongoing replication to minimize downtime. What change should the team make to the DMS task?

Accepted Answer

Modify the replication task to change the migration type to 'full-load-and-cdc'.. After a full load completes and the task stops, the team needs to enable ongoing replication to capture and apply changes made to the source database during the migration window. Modifying the DMS task to use the 'full-load-and-cdc' migration type allows the task to perform the initial full load and then seamlessly transition to Change Data Capture (CDC) to replicate incremental changes, minimizing downtime. This is the correct approach because DMS supports switching a completed full-load task to include CDC without re-running the full load.

Answer

Restart the replication task with the same settings.

Answer

Create a new replication instance and start a new full-load task.

Answer

Use AWS Schema Conversion Tool to convert the schema again.