DBS-C01 Practice Test 1 — 10 Questions

Question 1

A database administrator wants to receive an alert when an RDS instance's storage space drops below 10% of total allocated storage. Which AWS service should be used to set up this alert?

Accepted Answer

Amazon CloudWatch Alarms. Amazon CloudWatch Alarms is the correct service because it evaluates CloudWatch metrics against thresholds and triggers actions such as SNS notifications. For RDS, the FreeStorageSpace metric can be compared to a percentage of allocated storage using a metric math expression, and an alarm can fire when it drops below 10%. CloudWatch is the native monitoring and alerting layer for RDS.

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Amazon SNS

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AWS CloudTrail

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AWS Config

Question 2

A database specialist notices that an RDS MySQL instance's FreeableMemory metric is consistently below 100 MB. Which monitoring tool should be used to identify the queries consuming the most memory?

Accepted Answer

Performance Insights. Performance Insights is the correct tool because it provides detailed monitoring of database load and allows you to identify the queries consuming the most memory. It visualizes database load by wait events and top SQL, helping pinpoint memory-intensive queries. FreeableMemory is an OS-level metric, but Performance Insights drills down to the SQL level.

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Amazon S3 access logs

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AWS CloudTrail

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CloudWatch Logs

Question 3

A company is migrating its on-premises Oracle database to Amazon RDS for Oracle. The database specialist needs to monitor the migration process and ensure data consistency. Which TWO AWS services should be used together to continuously monitor the replication lag and data integrity?

Accepted Answer

AWS Database Migration Service (AWS DMS). AWS DMS is the correct service because it is specifically designed for database migrations and provides built-in monitoring of replication lag via the 'CDC latency' metric. Amazon CloudWatch is the correct complementary service because it collects and visualizes DMS metrics, including replication lag and task status, and can trigger alarms if data integrity or latency thresholds are breached.

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Amazon RDS Performance Insights

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AWS Schema Conversion Tool (AWS SCT)

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AWS Glue

Question 4

A company is migrating a PostgreSQL database to Amazon Aurora PostgreSQL. They have set up AWS DMS with change data capture (CDC). However, after the initial load, the CDC replication is experiencing high latency. What is the MOST likely cause?

Accepted Answer

The source database has large transactions that are not committed quickly.. Large uncommitted transactions on the source database cause DMS CDC to buffer changes until the transaction commits, leading to high latency. DMS must wait for the commit record before applying changes to the target Aurora instance, and during this time, CDC replication stalls, accumulating a backlog of changes.

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The target Aurora instance has insufficient storage.

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The DMS instance is using an older engine version.

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The network bandwidth is too low.

Question 5

A database specialist needs to monitor the performance of an Amazon Aurora PostgreSQL cluster and identify the top SQL statements by total time. Which AWS tool provides this information with minimal setup?

Accepted Answer

AWS Performance Insights with the Aurora PostgreSQL cluster.. AWS Performance Insights provides a user-friendly dashboard that shows top SQL statements by database load, including total time. It requires only enabling the feature on the Aurora cluster, with no additional agents or configuration. Other options either provide OS metrics, require log parsing, or are for auditing, not performance analysis.

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Amazon CloudWatch Logs Insights with Aurora PostgreSQL error logs.

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AWS CloudTrail with database activity streams.

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Amazon RDS Enhanced Monitoring with OS metrics.

Question 6

A company is using an Amazon RDS for MySQL DB instance. The security team requires that all database connections be encrypted in transit. Which configuration step ensures this requirement is met?

Accepted Answer

Set the 'require_secure_transport' parameter to 1 in the DB parameter group.. For Amazon RDS for MySQL, encryption in transit is enforced by setting the require_secure_transport parameter to 1 in the DB parameter group. This forces all client connections to use SSL/TLS, rejecting any unencrypted connection attempts. The parameter is dynamic and can be applied without a reboot in most cases.

Answer

Enable encryption at rest for the RDS instance.

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Store the database password in AWS Secrets Manager.

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Modify the network ACL to only allow traffic on port 3306.

Question 7

A database team is migrating an on-premises Oracle database to Amazon Aurora PostgreSQL. The team needs to ensure minimal downtime and data consistency. Which approach should be used?

Accepted Answer

Use AWS Database Migration Service (DMS) with ongoing replication using change data capture (CDC). AWS DMS with ongoing replication using change data capture (CDC) is the correct approach because it enables a live migration with minimal downtime. DMS can perform a full load of the Oracle database and then continuously replicate ongoing changes from Oracle to Aurora PostgreSQL, ensuring data consistency at the point of cutover. This method avoids the need for a long maintenance window and supports heterogeneous migrations with automatic schema conversion.

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Use the PostgreSQL foreign data wrapper (FDW) to link the Oracle database

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Use AWS Server Migration Service (SMS) to replicate the database

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Use pg_dump and pg_restore to migrate the data during a maintenance window

Question 8

A company stores sensitive data in an Amazon S3 bucket that is accessed by an Amazon Redshift cluster. The security team requires that the data in transit between Redshift and S3 be encrypted. Which configuration ensures this?

Accepted Answer

Ensure that the Redshift cluster has SSL enabled, which encrypts data in transit by default for COPY/UNLOAD operations to S3.. Redshift automatically uses SSL encryption for data in transit when moving data to and from S3 using COPY/UNLOAD commands. Option A is incorrect because server-side encryption (SSE-S3) encrypts data at rest, not in transit. Option C is incorrect because client-side encryption encrypts data before sending, but Redshift handles this automatically with SSL. Option D is incorrect because VPC endpoints do not encrypt data in transit; they provide private connectivity.

Answer

Enable server-side encryption (SSE-S3) on the S3 bucket.

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Configure a VPC endpoint for S3.

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Use client-side encryption on the data before uploading to S3.

Question 9

Which TWO of the following are recommended best practices for designing a relational database on Amazon RDS? (Select TWO.)

Accepted Answer

Use read replicas to scale read-heavy workloads. Amazon RDS read replicas offload read traffic from the primary DB instance, improving performance for read-heavy workloads by providing additional read-only endpoints. This is a core best practice for scaling read capacity without increasing load on the source instance.

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Use LOB data types to store large text fields

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Use non-EBS-optimized instances to reduce costs

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Store large binary objects (BLOBs) in the database

Question 10

A company is migrating an on-premises Oracle database to Amazon RDS for Oracle. The database size is 500 GB. The migration must have minimal downtime. Which AWS service should be used to perform the migration?

Accepted Answer

AWS Database Migration Service (DMS). AWS Database Migration Service (DMS) is the correct choice because it supports heterogeneous migrations from Oracle to Amazon RDS for Oracle with minimal downtime. DMS can perform continuous replication using Oracle's change data capture (CDC) via LogMiner or binary reader, allowing the source database to remain operational during the migration. This makes it ideal for a 500 GB database where downtime must be minimized.

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AWS Snowball Edge

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AWS DataSync

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Amazon RDS for Oracle snapshot copy