DBS-C01 Deployment and Migration Practice Test 9 — 15 Questions

Question 1

A company is deploying a new web application that uses Amazon RDS for PostgreSQL. The database must be highly available with automatic failover across two Availability Zones. Which deployment option meets this requirement?

Accepted Answer

Deploy RDS PostgreSQL with Multi-AZ configuration.. Multi-AZ deployment provides automatic failover. Option B (single-AZ) lacks HA. Option C (read replica) is for read scaling, not automatic failover. Option D (cross-region) is more complex and costly.

Answer

Deploy RDS PostgreSQL in a cross-region replication setup.

Answer

Deploy RDS PostgreSQL in a single Availability Zone.

Answer

Deploy RDS PostgreSQL with a read replica in another AZ.

Question 2

A company is migrating a 500 GB MongoDB database to Amazon DocumentDB. The migration must have minimal impact on the source database. Which approach should the company take?

Accepted Answer

Use AWS Database Migration Service (DMS) with MongoDB as source and DocumentDB as target.. AWS DMS supports MongoDB as a source and DocumentDB as a target, with ongoing replication to minimize downtime. Option A (mongorestore) causes high impact. Option C (export/import) causes impact. Option D (AWS SCT) is not for migration itself.

Answer

Use mongodump to export the data, then use mongorestore to import into DocumentDB.

Answer

Use mongoexport to export CSV, then use the DocumentDB import tool.

Answer

Use AWS Schema Conversion Tool (SCT) to convert schema, then copy data.

Question 3

A company needs to migrate a 3 TB Amazon RDS for SQL Server database to Amazon RDS for PostgreSQL. The migration must be automated and repeatable with minimal manual intervention. Which combination of services should be used?

Accepted Answer

Use AWS Schema Conversion Tool (SCT) to convert the schema, then use AWS DMS to migrate the data.. AWS SCT converts the schema, AWS DMS migrates the data with continuous sync. Option B: DMS only does not convert schema. Option C: SCT only does not migrate data. Option D: Data Migration Assistant is for SQL Server to SQL Server.

Answer

Use AWS SCT to convert the schema and export data to PostgreSQL-compatible format, then import.

Answer

Use AWS DMS with native SQL Server CDC to migrate directly to PostgreSQL.

Answer

Use Microsoft Data Migration Assistant to assess and migrate to PostgreSQL.

Question 4

A company is deploying a new application that requires a MySQL-compatible database with automatic scaling of compute and storage resources. Which AWS service should be used?

Accepted Answer

Amazon Aurora MySQL. Amazon Aurora with Auto Scaling capabilities (Aurora Auto Scaling for replicas, storage auto scaling). Option A: RDS MySQL has manual scaling only. Option C: DynamoDB is NoSQL. Option D: Redshift is data warehouse.

Answer

Amazon RDS for MySQL

Answer

Amazon DynamoDB

Answer

Amazon Redshift

Question 5

A company is migrating a 1 TB Amazon RDS for Oracle database to Amazon RDS for PostgreSQL. The migration must be completed within a 4-hour maintenance window. The database has a high volume of transactions. Which migration method minimizes risk of data loss?

Accepted Answer

Use AWS DMS with a full load and change data capture (CDC) enabled, with task restart and validation.. AWS DMS with task restart and validation ensures data consistency and minimizes data loss. Option A (SCT + DMS) may not complete within 4 hours. Option C (export/import) is time-consuming. Option D (log shipping) is not supported across engines.

Answer

Use AWS SCT to convert the schema, then use AWS DMS for full load and ongoing replication.

Answer

Set up Oracle log shipping to an EC2 instance, then restore to RDS PostgreSQL.

Answer

Export the Oracle database using Data Pump, import to PostgreSQL using pgloader.

Question 6

A company wants to deploy a globally distributed application with a DynamoDB table that uses optimistic locking. Which DynamoDB feature should be used to implement this?

Accepted Answer

DynamoDB Conditional Writes. DynamoDB conditional writes enable optimistic locking by checking a condition before writing. Option A: Transactions provide ACID but not optimistic locking. Option B: DynamoDB Streams is for change capture. Option D: Global tables provide multi-region replication.

Answer

DynamoDB Streams

Answer

DynamoDB Global Tables

Answer

DynamoDB Transactions

Question 7

A company is migrating a 10 TB Amazon RDS for MySQL database to Amazon Aurora MySQL. The migration must have minimal downtime and must support point-in-time recovery for the source during migration. Which approach meets these requirements?

Accepted Answer

Create a read replica of the source RDS instance, use AWS DMS with CDC from the read replica to Aurora, then promote Aurora.. AWS DMS with ongoing CDC from a read replica of the source minimizes impact and allows PITR. Option A (snapshot restore) causes downtime. Option B (mysqldump) causes downtime. Option D (DMS direct) may impact source performance.

Answer

Use mysqldump to export the database, import into Aurora, and point DNS to Aurora.

Answer

Use AWS DMS with CDC directly from the source RDS instance to Aurora.

Answer

Take a snapshot of the source RDS instance, restore to Aurora, and point DNS to Aurora.

Question 8

A company is migrating an on-premises PostgreSQL database to Amazon RDS for PostgreSQL. Which TWO AWS services can be used to assess the source database for compatibility and migration readiness?

Accepted Answer

AWS Schema Conversion Tool (SCT). AWS DMS can assess source database compatibility and perform data migration. AWS SCT can assess schema compatibility and convert the schema. Option C (CloudWatch) is for monitoring. Option D (Kinesis) is for streaming. Option E (Glue) is for ETL.

Answer

Amazon Kinesis

Answer

AWS Glue

Answer

Amazon CloudWatch

Question 9

A company is deploying a new Amazon RDS for Oracle database in a VPC. The database must be accessed by an application running on an EC2 instance in a different subnet. Which THREE steps are required to allow this access?

Accepted Answer

Configure the network ACL for the RDS subnet to allow inbound traffic from the EC2 subnet.. The security group of the RDS instance must allow inbound traffic from the EC2 security group. The VPC must have an association between subnets. The network ACLs must allow inbound traffic. Option D (Internet Gateway) is not needed for private connectivity. Option E (VPC peering) is not needed if in same VPC.

Answer

Create a VPC peering connection between the subnets.

Answer

Attach an Internet Gateway to the VPC.

Question 10

A company is migrating a 2 TB MongoDB database to Amazon DocumentDB. Which TWO factors should be considered when planning the migration?

Accepted Answer

Source MongoDB version compatibility with DocumentDB.. DocumentDB does not support all MongoDB features (e.g., some index types), so compatibility check is needed. Network bandwidth impacts migration speed. Option C: DocumentDB supports TLS. Option D: DocumentDB uses IAM for auth, not LDAP. Option E: DocumentDB uses its own backup, not S3.

Answer

DocumentDB stores backups in Amazon S3 automatically.

Answer

DocumentDB requires LDAP for authentication.

Answer

DocumentDB does not support encryption in transit.

Question 11

Refer to the exhibit. A company's production RDS MySQL instance 'mydb' is configured as shown. The application experiences write latency spikes during peak hours. Which action would most effectively reduce write latency?

Accepted Answer

Change the storage type to Provisioned IOPS (io1) and allocate sufficient IOPS.. The instance is single-AZ, so enabling Multi-AZ provides a standby in another AZ, but does not directly reduce write latency. Upgrading to storage optimized instances (db.r5d) is not necessarily. Enabling Multi-AZ with synchronous standby can increase write latency due to sync replication. Actually, Multi-AZ does not improve write performance; it adds sync replication overhead. However, the correct answer here is to enable Multi-AZ to improve availability and potentially reduce latency by offloading reads? No, write latency spikes are typically due to storage I/O. The instance uses gp2, which has baseline IOPS of 1500 for 500 GB. Provisioned IOPS (io1) would improve consistent write performance. Option D (increase allocated storage) increases baseline IOPS but not as effective as provisioned IOPS. Option A (Multi-AZ) might increase latency. Option B (read replica) helps reads. Option C (provisioned IOPS) directly improves write performance.

Answer

Create a Read Replica in a different region.

Answer

Increase the allocated storage to 1 TB to improve baseline IOPS.

Answer

Enable Multi-AZ deployment to provide a standby instance.

Question 12

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 13

Refer to the exhibit. A database specialist is taking a final snapshot of an RDS DB instance before deletion. The command returns the output shown. The snapshot is at 75% progress. What should the specialist do next?

Accepted Answer

Wait for the snapshot status to become 'available' before deleting the instance.. The snapshot is still creating. The specialist should wait for the snapshot to complete before deleting the instance. Option A (delete now) would cause snapshot to be incomplete. Option B (describe-db-snapshots to check) is redundant. Option C (stop the snapshot) is not possible. Option D (wait and check) is correct.

Answer

Use the describe-db-snapshots command with --db-snapshot-identifier to get more details.

Answer

Use the stop-db-instance command to pause the snapshot.

Answer

Delete the DB instance immediately; the snapshot will continue in the background.

Question 14

A company is migrating a 5 TB Oracle database to Amazon Aurora PostgreSQL. The database has a 4-hour maintenance window weekly. Which migration approach minimizes downtime?

Accepted Answer

Use AWS Database Migration Service (DMS) with change data capture (CDC).. Option B is correct because AWS DMS supports ongoing replication with minimal downtime. Option A is wrong because native export/import requires downtime. Option C is wrong because it adds unnecessary complexity. Option D is wrong because SCT is for schema conversion, not data migration.

Answer

Use Oracle Data Pump to export and pg_restore to import.

Answer

Use AWS Schema Conversion Tool (SCT) to convert schema and then copy data.

Answer

Use AWS DMS full load only and then manually sync.

Question 15

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.