DBS-C01 Practice Test 40 — 15 Questions

Question 1

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. Option D is correct because setting up replication from the on-premises Redis to ElastiCache using the replication features can achieve minimal downtime. Option A is wrong because AWS DMS does not support Redis as a source. Option B is wrong because taking a snapshot and restoring requires downtime during the restore process. Option C is wrong because the SAVE command is synchronous and can cause performance issues; BGSAVE is preferred.

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 2

A company is migrating a 2 TB Oracle database from on-premises to Amazon RDS for Oracle using AWS DMS. The migration completes successfully, but the new RDS instance shows higher CPU utilization than the on-premises database for the same workload. Which action is MOST likely to reduce CPU utilization on RDS?

Accepted Answer

Enable Oracle Multitenant architecture. Option A is correct because enabling Oracle Multitenant reduces overhead by consolidating containers. Option B is wrong because RDS does not allow direct instance type change without downtime. Option C is wrong because increasing storage does not directly reduce CPU. Option D is wrong because disabling backups is not recommended and may not be the cause.

Answer

Disable automated backups to free resources

Answer

Increase the allocated storage to improve IOPS

Answer

Change the RDS instance to a burstable class

Question 3

A company is planning to migrate a 1 TB SQL Server database to Amazon RDS for SQL Server. Which TWO factors should be considered when choosing the migration approach?

Accepted Answer

The need to modify the database schema for compatibility. Options A and C are correct. The acceptable downtime window determines whether offline or online migration is used, and the ability to modify the schema may require SCT. Option B is wrong because SQL Server Agent jobs can be migrated. Option D is wrong because the source SQL Server version affects compatibility. Option E is wrong because the number of concurrent users is not a primary factor.

Answer

The number of concurrent users accessing the database

Answer

Whether the database uses SQL Server Agent jobs

Answer

The version of the source SQL Server instance

Question 4

A company is migrating an on-premises PostgreSQL database to Amazon RDS for PostgreSQL. The database is 2 TB and the migration must have minimal downtime. Which TWO AWS services should be used together to accomplish this?

Accepted Answer

AWS Schema Conversion Tool (AWS SCT). AWS DMS provides data migration with ongoing replication, and AWS SCT can help convert schema if needed, but for homogeneous migration, DMS alone is sufficient. However, the question asks for two services; the combination of DMS and SCT is commonly used for heterogeneous migrations. For homogeneous, DMS alone is enough, but SCT can still be used to assess schema compatibility. Option E is incorrect because CloudEndure is for server migration.

Answer

AWS CloudFormation

Answer

AWS DataSync

Answer

AWS CloudEndure Migration

Question 5

A company is migrating a self-hosted Cassandra cluster to Amazon Keyspaces (for Apache Cassandra). The cluster has 10 nodes and handles 50,000 writes per second. Which migration strategy is MOST efficient?

Accepted Answer

Set up Keyspaces as a new datacenter in the existing Cassandra cluster using native replication.. Option A is correct because using native Cassandra replication allows seamless migration with zero downtime by adding Keyspaces as a new datacenter. Option B is wrong because DMS does not support Cassandra as a source for Keyspaces. Option C is wrong because CQL COPY is not suitable for high throughput writes and requires downtime. Option D is wrong because S3 export/import is a batch process, not real-time.

Answer

Export data using CQL COPY and import into Keyspaces.

Answer

Use AWS Glue to extract data from Cassandra and write to Keyspaces.

Answer

Use AWS DMS with Cassandra as source and Keyspaces as target.

Question 6

A company is moving a self-hosted MySQL database to Amazon Aurora MySQL. The current database uses InnoDB with full-text indexes and triggers. The migration must be done with zero downtime. Which approach meets these requirements?

Accepted Answer

Use AWS DMS with ongoing replication from the source MySQL database. AWS DMS can migrate MySQL to Aurora MySQL with ongoing replication (CDC), supporting InnoDB tables, full-text indexes, and triggers. Option A fails because mysqldump causes downtime. Option B fails because Aurora does not support replication from external MySQL. Option D is incorrect because S3 bucket loading is not supported for MySQL.

Answer

Use mysqldump to export the database and import into Aurora

Answer

Set up MySQL replication from on-premises to Aurora using native binlog replication

Answer

Export data to Amazon S3 and use Aurora's LOAD DATA FROM S3 command

Question 7

Which TWO AWS services can be used to migrate a MongoDB database to Amazon DocumentDB? (Choose 2.)

Accepted Answer

AWS Database Migration Service (AWS DMS). AWS DMS supports migration from MongoDB to DocumentDB, and MongoDB's native mongodump and mongorestore can be used. Option C (S3) is not directly used. Option D (DataSync) is for file data. Option E (Kinesis) is for streaming data.

Answer

AWS DataSync

Answer

Amazon S3

Answer

Amazon Kinesis Data Streams

Question 8

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.. Option D is correct because even though the source is publicly accessible, DMS is in a VPC and cannot directly access public IPs unless the VPC has an internet gateway and the route table allows it. The security group of the source must allow inbound traffic from the DMS replication instance's security group. Option A is wrong because DMS does not require a VPC endpoint for source connectivity. Option B is wrong because the replication instance subnet group is already set. Option C is wrong because the source database should not be in public subnet; it can be private with proper routing.

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 9

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. Option C is correct because creating an Aurora read replica from an RDS MySQL instance and then promoting it to a standalone Aurora cluster provides minimal downtime and leverages the built-in replication. Option A is wrong because taking a snapshot and restoring to Aurora requires downtime during the restore process. Option B is wrong because AWS DMS with full load plus CDC can achieve minimal downtime but is more complex and slower than using native replication. Option D is wrong because migrating to a larger RDS instance does not address the need to move to Aurora.

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 10

Refer to the exhibit. A company is creating an IAM policy for a migration engineer who needs to perform a database migration from an on-premises SQL Server to Amazon RDS for SQL Server using AWS DMS. The policy is attached to the engineer's IAM user. Which additional permission is required for the engineer to create a DMS replication instance?

Accepted Answer

ec2:CreateInstance (or equivalent). Option A is correct because to create a DMS replication instance, the IAM user needs permissions to create EC2 instances, as replication instances run on EC2. The policy currently allows creating DMS tasks but not the replication instance itself. Option B is wrong because DMS endpoints do not require EC2 permissions. Option C is wrong because S3 permissions are not needed for the replication instance. Option D is wrong because KMS permissions are for encryption keys, not for creating the replication instance.

Answer

kms:CreateKey

Answer

dms:CreateEndpoint

Answer

s3:PutObject

Question 11

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. Option C is correct because SCT may not always generate optimal indexes for Aurora PostgreSQL, leading to performance issues. Option A is wrong because Aurora PostgreSQL supports partitioning. Option B is wrong because DMS does not affect query execution plans. Option D is wrong because storage performance should not cause query slowness.

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

Question 12

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 DMS can handle large data migrations efficiently. Option A is incorrect because pg_dump is for PostgreSQL, not Oracle. Option C is incorrect because S3 is not suitable for direct database migration. Option D is incorrect because AWS SCT is for schema conversion, not data migration.

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 13

A company is planning to migrate a MongoDB database to Amazon DocumentDB. The database has several sharded collections. Which migration strategy should be used?

Accepted Answer

Use AWS DMS with MongoDB as source and DocumentDB as target, enabling ongoing replication.. Option A is correct because AWS DMS supports MongoDB as a source and DocumentDB as a target for continuous migration. Option B is wrong because mongodump/mongorestore does not handle sharding well and requires downtime. Option C is wrong because DocumentDB does not support native replication from MongoDB. Option D is wrong because DocumentDB does not have a sharding feature like MongoDB.

Answer

Set up MongoDB replica set to replicate directly to DocumentDB.

Answer

Use AWS Schema Conversion Tool (SCT) to convert the schema, then manually migrate data.

Answer

Export data using mongodump and import using mongorestore.

Question 14

A company is migrating a 200 GB Oracle database to Amazon RDS for Oracle. Which TWO steps should be taken to ensure a successful migration? (Choose two.)

Accepted Answer

Use AWS DMS with full load and ongoing replication.. Options B and D are correct. Using AWS SCT helps convert the schema and identify potential issues. Using AWS DMS with ongoing replication minimizes downtime. Option A is wrong because Oracle to RDS for Oracle is homogeneous; DMS supports it. Option C is wrong because manual export/import is error-prone and causes downtime. Option E is wrong because encrypting the source database adds complexity and may not be necessary.

Answer

Enable TDE encryption on the source database before migration.

Answer

Use AWS DMS only for heterogeneous migrations; use Oracle Data Pump instead.

Answer

Export the database using expdp and import using impdp.

Question 15

A company is migrating a 1 TB Oracle database to Amazon RDS for Oracle. The source database has a high volume of small transactions. The migration must minimize source database impact. Which AWS DMS configuration should be used?

Accepted Answer

Use full load only and disable ongoing replication. Using a full load without CDC for the initial migration minimizes impact because CDC adds overhead. Batch-optimized applies changes in batches, but CDC still runs. Using multiple tasks increases overhead. Full load only is the least impactful.

Answer

Use batch-optimized apply mode

Answer

Use full load with CDC (ongoing replication)

Answer

Use multiple DMS tasks to parallelize the migration