DBS-C01 Practice Test 34 — 15 Questions

Question 1

A company is deploying a new web application that uses Amazon RDS for MySQL. The application has unpredictable read traffic spikes. The company wants to minimize read latency and automatically scale read capacity. What is the MOST cost-effective solution?

Accepted Answer

Create an Amazon RDS read replica and configure the application to use it for read traffic. A Multi-AZ deployment provides high availability but does not offload reads. Read replicas offload read traffic and can be scaled manually or via auto-scaling with a custom solution. RDS Proxy is for connection management, not read scaling. ElastiCache is a caching layer but requires application changes and adds cost. Read replicas are the most cost-effective for read scaling.

Answer

Use Amazon ElastiCache as a caching layer

Answer

Use Amazon RDS Proxy to manage connections

Answer

Deploy the RDS instance in a Multi-AZ configuration

Question 2

A company is migrating a MySQL database to Amazon Aurora MySQL. The migration must be completed with minimal downtime. Which TWO methods can achieve this? (Choose two.)

Accepted Answer

Create an Aurora MySQL read replica from the external MySQL instance using binlog replication. Using an Aurora read replica from an external MySQL instance is possible via the MySQL binlog replication, but it requires setting up replication from on-premises to Aurora. This is a valid method for minimal downtime. Creating an Aurora clone is for cloning existing Aurora clusters, not migration. Using DMS with ongoing replication is the standard approach. Taking a snapshot and restoring requires downtime. Enabling binlog replication is part of setting up a read replica. So correct are B and D. Option A: clone is not for migration. Option C: snapshot restore requires downtime. Option E: binlog replication alone is not a migration method; it's a configuration step.

Answer

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

Answer

Create an Aurora clone from the source database

Answer

Enable binlog replication on the source MySQL instance

Question 3

A company is migrating a 500 GB SQL Server database to Amazon RDS for SQL Server. The migration must minimize downtime and support ongoing replication. Which TWO AWS services should be used together?

Accepted Answer

AWS Database Migration Service (DMS). Options A and D are correct. AWS DMS can perform ongoing replication, and AWS SCT can convert the schema and assess any incompatibilities. Option B is wrong because Snowball is for offline transfer, not minimal downtime. Option C is wrong because RDS does not support native SQL Server replication as a target. Option E is wrong because Lambda is not needed for migration.

Answer

AWS Lambda

Answer

AWS Snowball Edge

Answer

AWS RDS SQL Server native backup and restore

Question 4

Refer to the exhibit. An IAM policy is attached to an IAM user that performs database migrations. When the user tries to start an AWS DMS replication task that writes to the RDS instance 'targetdb', the task fails with an access denied error. Which additional permission is required?

Accepted Answer

dms:DescribeReplicationInstances. The policy allows dms:StartReplicationTask but does not include the necessary DMS permissions for the replication instance or endpoints. Specifically, the user needs dms:CreateReplicationInstance and dms:CreateEndpoint. Also, the task may need to pass a role. But from the error, likely missing dms:StartReplicationTask? No, that's allowed. The error might be due to missing dms:CreateReplicationTask? That is allowed. Actually, the task might need to describe endpoints or replication instances. The missing permission is likely dms:DescribeReplicationInstances or dms:DescribeEndpoints. However, the most common missing permission is dms:DescribeReplicationInstances to list available instances. Option D (dms:DescribeReplicationInstances) is plausible. Option A (rds:ModifyDBInstance) is allowed for targetdb. Option B (dms:CreateReplicationInstance) is not needed if instance exists. Option C (dms:CreateEndpoint) is needed if endpoint not created. But the exhibit shows the task already created? The user might need to describe replication instances to choose one. However, the task was started, so the instance must exist. The most likely missing permission is dms:DescribeReplicationInstances.

Answer

dms:CreateEndpoint

Answer

dms:CreateReplicationInstance

Answer

rds:ModifyDBInstance on the source database

Question 5

A company is migrating a self-managed PostgreSQL database with extensions (PostGIS, pg_stat_statements) to Amazon RDS for PostgreSQL. After migration, they find that the extensions are not available. What is the most likely cause?

Accepted Answer

The required extensions are not included in the default parameter group and must be manually added to shared_preload_libraries.. Option B is correct because RDS for PostgreSQL supports many extensions but not all; PostGIS is supported but may require enabling. Option A is wrong because extensions are supported. Option C is wrong because extensions are allowed. Option D is wrong because the question is about extensions not available.

Answer

The extensions are incompatible with the RDS engine version.

Answer

The RDS instance is not configured to allow extensions.

Answer

RDS does not support any PostgreSQL extensions.

Question 6

A company is deploying a new Amazon Aurora MySQL database. The development team requires a separate database instance for testing that is a clone of the production database but does not require the same level of performance. What is the MOST cost-effective way to create this test database?

Accepted Answer

Use the Aurora cloning feature to create a clone of the production cluster. Aurora cloning creates a logical copy of the cluster volume that is space-efficient and fast, using copy-on-write semantics. Creating a new instance from a snapshot incurs storage costs and takes longer. Read replicas are for read scaling, not cloning. Using a different DB instance class does not reduce storage.

Answer

Create a new Aurora cluster from the latest snapshot of the production cluster

Answer

Create a read replica of the production cluster and promote it to a standalone cluster

Answer

Create a new Aurora cluster and use a smaller DB instance class

Question 7

A company is migrating a 10 TB Oracle data warehouse to Amazon Redshift. The migration must minimize data transfer costs and ensure data integrity. Which TWO steps should the company take?

Accepted Answer

Use AWS Schema Conversion Tool (SCT) to convert the Oracle schema to Redshift. Options A and D are correct. AWS SCT can assess the schema and convert it for Redshift. AWS Snowball Edge can transfer the large dataset offline to reduce network costs. Option B is wrong because DMS may incur high network costs and time. Option C is wrong because Redshift Spectrum queries data in S3, not for migration. Option E is wrong because Kinesis is for streaming, not for bulk migration.

Answer

Use AWS DMS to replicate data directly over the internet

Answer

Use Amazon Kinesis Data Streams to stream data to Redshift

Answer

Use Amazon Redshift Spectrum to query data in S3 after loading

Question 8

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 a custom application to capture MongoDB oplog changes and apply to DocumentDB.. Option D is correct because DocumentDB doesn't support change streams from MongoDB 4.0; using a custom replication tool is needed. Option A is wrong because DocumentDB has no native replication capability. Option B is wrong because DMS supports MongoDB to DocumentDB but only offline full load. Option C is wrong because it requires downtime.

Answer

Use AWS DMS with ongoing replication from MongoDB 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 9

A company is deploying a new MySQL database on Amazon RDS. They need to ensure that the database is automatically backed up daily and retained for 30 days. Which TWO configurations should be set? (Choose 2)

Accepted Answer

Set backup retention period to 30 days.. Options A and D are correct because automated backups are enabled by default and retention period can be set up to 35 days. Option B is wrong because manual snapshots are separate. Option C is wrong because it's not about backups. Option E is wrong because it doesn't set retention.

Answer

Set backup window.

Answer

Enable Multi-AZ deployment.

Answer

Create a manual snapshot daily.

Question 10

Refer to the exhibit. A database administrator is trying to use AWS DMS to migrate data from an on-premises Oracle database to Amazon RDS for Oracle. The DMS replication instance is in the same VPC as the RDS instance. The administrator receives an access denied error when starting the replication task. The IAM policy attached to the DMS replication instance is shown. What is the MOST likely cause of the error?

Accepted Answer

The IAM policy does not include permissions for the source database endpoint. The IAM policy allows dms:CreateReplicationTask and dms:StartReplicationTask on replication tasks, and rds:DescribeDBInstances. However, DMS needs permissions to describe RDS instances (rds:DescribeDBInstances is allowed) and to access the source endpoint (on-premises). But the error is likely due to missing permissions on the source endpoint or network connectivity. However, the most common issue is that the DMS replication instance needs permissions to access the source database, but the policy only allows actions on replication tasks, not on endpoints. DMS also needs dms:CreateEndpoint and dms:TestConnection. However, the policy shown is too restrictive. The question asks for the MOST likely cause given the error: the IAM policy does not include permissions for dms:CreateEndpoint or dms:TestConnection. But the error is when starting the task, which may be due to missing permissions on the source endpoint. However, the best answer is that the IAM policy does not include the necessary permissions for the source endpoint. Option C is correct because DMS needs permissions to describe endpoints and test connections.

Answer

The IAM policy does not allow the dms:CreateReplicationInstance action

Answer

The RDS instance is not in the same VPC as the DMS replication instance

Answer

The DMS replication instance is not associated with the IAM role

Question 11

A developer needs to deploy an Amazon RDS for MySQL DB instance that is accessible only from a specific EC2 instance in a VPC. Which configuration ensures this?

Accepted Answer

Place the RDS instance in the same VPC as the EC2 instance and configure a security group inbound rule referencing the EC2 security group. Option C is correct because placing the RDS instance in the same VPC and using a security group that allows inbound traffic from the EC2 instance's security group ensures restricted access. Option A is wrong because public accessibility would expose the DB to the internet. Option B is wrong because a network ACL applies at subnet level, not instance level. Option D is wrong because an IAM role does not control network access.

Answer

Use an IAM role to allow the EC2 instance to connect to the RDS instance

Answer

Enable public accessibility and assign a public IP to the RDS instance

Answer

Place RDS and EC2 in different subnets and configure a network ACL

Question 12

An administrator runs the CLI command shown in the exhibit and sees the output. The DB instance 'mydb' is currently running MySQL 5.7.22. What does the output indicate?

Accepted Answer

The DB instance has a pending minor version upgrade to 5.7.23. Option A is correct because the PendingModifiedValues show EngineVersion 5.7.23, indicating a pending minor version upgrade. Option B is wrong because the parameter group is the default, not custom. Option C is wrong because the password is pending modification, but the question asks about the version. Option D is wrong because the output does not show a failure.

Answer

The master user password has been changed

Answer

The DB instance has failed to apply modifications

Answer

The DB instance is using a custom DB parameter group

Question 13

A company is migrating a 1 TB SQL Server database to Amazon RDS for SQL Server. The migration requires minimal downtime and must support ongoing changes. Which TWO AWS services should be used together to achieve this? (Choose two.)

Accepted Answer

AWS Database Migration Service (AWS DMS) and AWS Schema Conversion Tool (AWS SCT). AWS DMS is the primary service for database migration with minimal downtime and ongoing replication. AWS SCT is used to convert the schema from SQL Server to RDS SQL Server (which may not need conversion) but more importantly to assess and convert any incompatible objects. However, for a like-to-like migration (SQL Server to SQL Server), SCT may not be required, but the question says 'migrating' and 'ongoing changes', so DMS is necessary. For minimal downtime, DMS uses Change Data Capture (CDC). To use CDC on SQL Server, you need to enable it, and SCT can help with schema conversion if needed. But the best pair is DMS and SCT because SCT can help with any schema incompatibilities and DMS handles data. Option A (DMS + SCT) is the standard recommendation for heterogeneous and homogeneous migrations. Option B (DMS + Snowball) is for large initial loads, but with 1 TB and minimal downtime, DMS alone may suffice. Option C (SCT + Snowball) doesn't include DMS for ongoing replication. Option D (DMS + Direct Connect) is about network, not a service. Option E (DMS + Lambda) is not typical. So correct is A and B? Wait: The question asks for TWO services. The typical best practice for minimal downtime is to use DMS with ongoing replication. For large databases, you might use Snowball for initial load and then DMS for CDC. So DMS and Snowball is a valid combination. Also DMS and SCT is also valid for schema conversion. Which two are correct? The question is 'Which TWO' and there are exactly two correct. I'll set correct options as A and B, but need to ensure exactly two. I'll make A: DMS and SCT, B: DMS and Snowball. Both are valid. But the stem says 'must support ongoing changes', so DMS is needed. SCT is for schema conversion, which may be needed but not always. Snowball is for initial load. Both are valid. I'll choose A and B as correct. Explanation: DMS is required for ongoing replication; SCT helps with schema conversion; Snowball helps with initial load for large databases.

Answer

AWS Schema Conversion Tool (AWS SCT) and AWS Snowball

Answer

AWS Database Migration Service (AWS DMS) and AWS Direct Connect

Answer

AWS Database Migration Service (AWS DMS) and AWS Lambda

Question 14

A company wants to deploy a highly available Amazon RDS for MySQL database across two Availability Zones. Which feature should be enabled?

Accepted Answer

Multi-AZ deployment. Option A is correct because Multi-AZ deployment provides automatic failover to a standby in a different AZ. Option B is wrong because read replicas are for read scaling, not high availability. Option C is wrong because automatic backups are for point-in-time recovery. Option D is wrong because Enhanced Monitoring provides metrics, not HA.

Answer

Read replicas in a different AZ

Answer

Automated backups with retention

Answer

Enhanced Monitoring

Question 15

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.. Options A and C are correct. TDE requires exporting the certificate to decrypt at the target. DMS CDC requires full supplemental logging. Option B is wrong because SCT is not needed. Option D is wrong because the database must be in full recovery model for CDC. Option E is wrong because using a backup over S3 is possible but does not address TDE or CDC.

Answer

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

Answer

Use native SQL Server backup and restore to S3.

Answer

Use AWS SCT to convert the schema to Amazon Aurora.