DBS-C01 Management and Operations Practice Test 18 — 15 Questions

Question 1

A company runs a critical application on an Amazon RDS for MySQL DB instance. The company requires that the database be available with minimal downtime during a disaster recovery scenario. The current RDS instance is in us-east-1. The company wants to have a standby database in us-west-2 with automatic failover. What should the company do to meet this requirement?

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

Accepted Answer

Create a cross-region read replica in us-west-2. Configure automatic failover using Amazon Route 53 health checks.. An RDS cross-region read replica can be promoted to a standalone instance in a disaster, providing automatic failover with minimal downtime when combined with Route 53 health checks. Option A (Multi-AZ in us-west-2) does not provide cross-region failover; Multi-AZ only provides high availability within a single region. Option B (snapshots) requires manual restoration and incurs downtime. Option D (Multi-AZ in us-east-1) only protects against Availability Zone failures within us-east-1, not region failures. Therefore, option C is the correct solution.

Answer

Create a Multi-AZ deployment in us-west-2 and use Amazon Route 53 to failover.

Answer

Take daily snapshots and copy them to us-west-2. Restore from snapshot in us-west-2 during a disaster.

Answer

Create a Multi-AZ deployment in us-east-1.

Question 2

A company is using Amazon DynamoDB with on-demand capacity mode. The company notices that during a flash sale, the write requests are throttled. What is the most likely cause of the throttling?

Accepted Answer

A hot partition is causing throttling even though the table uses on-demand capacity.. For a DynamoDB table in on-demand capacity mode, throttling is typically caused by a hot partition. On-demand mode automatically scales table-level throughput, but if a single partition key is heavily accessed (e.g., during a flash sale), that partition can exceed its individual capacity limit, resulting in throttled write requests. This is the most likely cause, making option C correct. Option A (maximum throughput limit) does not apply because on-demand has no fixed maximum; option B (auto scaling) is irrelevant since on-demand manages scaling automatically; option D (provisioned WCUs) is not used in on-demand mode.

Answer

The table has reached its maximum throughput limit for on-demand mode.

Answer

The table is not configured for auto scaling.

Answer

The provisioned write capacity units (WCUs) are set too low.

Question 3

A company is using Amazon RDS for PostgreSQL with read replicas to offload read traffic. The company wants to ensure that the read replicas are always in sync with the primary instance. Which metric should the company monitor to detect replication lag?

Accepted Answer

ReplicaLag. The correct metric to monitor for replication lag in Amazon RDS for PostgreSQL read replicas is ReplicaLag. This metric is available in CloudWatch and directly indicates the time difference between the primary instance and the read replica. Option A (DiskQueueDepth) measures the number of pending I/O requests, not replication lag. Option C (TransactionLogsDiskUsage) measures the amount of transaction logs, which is related but not a direct lag metric. Option D (ReadLatency) measures the latency of read operations, not the synchronization delay.

Answer

DiskQueueDepth

Answer

TransactionLogsDiskUsage

Answer

ReadLatency

Question 4

A company is deploying an Amazon Aurora MySQL database. The company requires that the database withstand the loss of two copies of data without impacting write availability. Which configuration should the company use?

Accepted Answer

Aurora with 6 copies of data across 3 Availability Zones. Aurora MySQL stores 6 copies of data across 3 Availability Zones. The database can withstand the loss of up to two copies without affecting write availability, provided the copies are distributed across AZs. Option D (6 copies across 3 AZs) is correct. Option A (3 copies in 3 AZs) is incorrect because Aurora uses 6 copies, not 3. Option B (2 copies in 2 AZs) provides insufficient redundancy. Option C (3 copies in 2 AZs) is not the architecture; Aurora uses 6 copies across 3 AZs.

Answer

Aurora with 3 copies of data in 3 Availability Zones

Answer

Aurora with 2 copies of data in 2 Availability Zones

Answer

Aurora with 3 copies of data in 2 Availability Zones

Question 5

A company is using Amazon DynamoDB for a gaming application. The application stores player scores in a table with a partition key of player_id and a sort key of timestamp. The company wants to query the top 10 scores for a given player efficiently. Which TWO steps should the company take to optimize this query?

Accepted Answer

Use the Query API with the LSI and scan index forward set to false to get the top scores.. The correct answers are A and B. A local secondary index (LSI) on the score attribute (option B) allows efficient sorting of items within the same partition key (player_id) by score. Using the Query API on this LSI with scanIndexForward set to false (option A) retrieves the top scores in descending order. Option C (Scan with filter) is inefficient as it reads the entire table. Option D (LSI on timestamp) is redundant because the base table already has timestamp as sort key and does not sort by score. Option E (GSI on score) would not be efficient for per-player queries because you would need to query by score globally, not per player.

Answer

Use a Scan operation with a filter expression to retrieve the top scores.

Answer

Create a local secondary index on the timestamp attribute.

Answer

Create a global secondary index (GSI) on the score attribute.

Question 6

A company is migrating a large on-premises Oracle database to Amazon RDS for Oracle. The database is 5 TB in size, and the migration must be completed within a week. The company has a dedicated 10 Gbps AWS Direct Connect connection. Which TWO AWS services should the company use to minimize downtime during the migration?

Accepted Answer

AWS Schema Conversion Tool (AWS SCT). AWS DMS can handle ongoing replication to minimize downtime. AWS SCT can convert the schema if needed, and AWS DMS can migrate data. AWS Snowball is for offline data transfer, which may not be needed with Direct Connect. RDS is the target, not a migration service. AWS DataSync is for file data, not databases. The correct options are A and D.

Answer

AWS DataSync

Answer

AWS Snowball

Answer

Amazon RDS for Oracle

Question 7

A company is running an Amazon RDS for MySQL Multi-AZ DB instance. The company wants to implement a backup strategy that meets a recovery point objective (RPO) of 5 minutes and a recovery time objective (RTO) of 1 hour. Which THREE steps should the company take to meet these objectives?

Accepted Answer

Configure AWS Backup to copy automated backups to another region.. Automated backups with a 35-day retention period (B) enable point-in-time recovery within the last 35 days, supporting an RPO of 5 minutes. Configuring AWS Backup to copy automated backups to another region (A) provides cross-region disaster recovery, helping meet the RTO of 1 hour by restoring in a different region. Creating a cross-region read replica (D) allows for quick failover by promoting the replica, which can significantly reduce RTO. Option C (Single-AZ) is less resilient and does not help meet RPO/RTO. Option E (daily manual snapshots) cannot achieve a 5-minute RPO due to manual timing.

Answer

Change the DB instance to a Single-AZ configuration to reduce costs.

Answer

Take daily manual snapshots and copy them to another region.

Question 8

A company is running an Amazon RDS for MySQL Multi-AZ DB instance. They notice increased latency during peak hours. The DB instance type is db.r5.large, and the storage is General Purpose SSD (gp2) with 500 GB. The application is read-heavy with frequent SELECT queries. Which action would most likely resolve the latency issue without changing the DB instance class?

Accepted Answer

Create an Amazon RDS read replica in the same region.. Adding a read replica offloads read traffic from the primary instance, reducing latency. Option A is wrong because enabling Performance Insights is for monitoring and analysis, not directly improving performance. Option C is wrong because Multi-AZ is for high availability, not read scaling. Option D is wrong because increasing storage size may improve IOPS but does not directly address the read load.

Answer

Enable Performance Insights and analyze queries.

Answer

Enable Multi-AZ on the existing DB instance.

Answer

Increase the allocated storage to 1,000 GB.

Question 9

An administrator is troubleshooting a permissions issue. A user with the IAM policy shown is unable to share an automated system snapshot with another AWS account. Which action should the administrator take to resolve this issue?

Accepted Answer

Change the Resource to "arn:aws:rds:us-east-1:123456789012:snapshot:automated:*".. The policy allows actions on DB snapshots, but automated snapshots have the resource type 'automated-snapshot' and require explicit resource ARN instead of '*'. Option A is wrong because the policy already includes the necessary actions. Option B is wrong because the issue is not about cross-region copying. Option D is wrong because the issue is not about manual snapshots.

Answer

Add the rds:ModifyDBSnapshotAttribute action to the policy.

Answer

Add the rds:CopyDBSnapshot action for cross-region copy.

Answer

Change the Resource to "arn:aws:rds:us-east-1:123456789012:snapshot:rds:*".

Question 10

A company is using Amazon DynamoDB for a high-traffic web application. The table has on-demand capacity mode. During a marketing event, the application experiences throttling. Which TWO actions should the database specialist take to prevent throttling in future events?

Accepted Answer

Pre-create a DynamoDB global table to distribute write traffic.. Options C and E are correct. Option C: Pre-creating a DynamoDB global table can distribute write traffic across multiple regions, reducing the load on any single table and helping to prevent throttling during traffic spikes. Option E: Implementing DynamoDB Accelerator (DAX) offloads read traffic from the main table, reducing read capacity consumption and potential throttling. Option A is incorrect because on-demand mode does not use read capacity units; it scales automatically. Option B is incorrect because switching to provisioned capacity requires capacity planning and does not automatically prevent throttling. Option D is incorrect because decreasing write capacity would likely worsen throttling.

Answer

Increase the read capacity units of the table.

Answer

Switch the table to provisioned capacity mode and increase write capacity units.

Answer

Decrease the write capacity units to reduce throttling.

Question 11

A company is migrating an on-premises Oracle database to Amazon RDS for Oracle. The database is 2 TB in size and has a 24/7 uptime requirement. The migration must have minimal downtime and support ongoing replication. Which TWO services or features should the specialist use to accomplish this?

Accepted Answer

An AWS DMS replication instance.. Options C and E are correct. Option C: An AWS DMS replication instance is required to run AWS DMS tasks, including migration with ongoing replication. Option E: AWS DMS with change data capture (CDC) enables ongoing replication with minimal downtime. Option D is incorrect because AWS Schema Conversion Tool (AWS SCT) is used for heterogeneous migrations (e.g., Oracle to PostgreSQL), not for homogeneous Oracle-to-Oracle migrations. Option A is incorrect because Oracle Data Guard is not supported for direct replication to Amazon RDS for Oracle; DMS is used instead. Option B is incorrect because cross-Region automated backups are a backup feature, not a migration tool for minimal downtime migration.

Answer

Oracle Data Guard to replicate to RDS.

Answer

Amazon RDS cross-Region automated backups.

Answer

AWS Schema Conversion Tool (AWS SCT).

Question 12

A database specialist runs the CLI command shown. The output indicates the instance is Multi-AZ and available. The application, however, is experiencing intermittent connection timeouts to the database endpoint. What is the most likely cause?

Accepted Answer

A failover occurred due to a Multi-AZ event.. A Multi-AZ failover can cause transient connection timeouts if the application does not have proper retry logic. The instance status shows 'available', so storage is not full (eliminating D). MySQL 8.0.28 is a supported version (eliminating B). The instance class db.r5.xlarge is current generation and available in the region (eliminating C). Therefore, the intermittent timeouts are most likely due to a failover event.

Answer

The MySQL engine version is not supported.

Answer

The DB instance class is not available in the current region.

Answer

The database storage is full.

Question 13

A company is using Amazon DynamoDB with auto scaling enabled. The table's read capacity is set to a minimum of 100 and maximum of 1000 read capacity units (RCUs). The actual consumed read capacity is consistently at 200 RCUs. What should the database specialist do to optimize costs without impacting performance?

Accepted Answer

Lower the minimum read capacity to 200 RCUs.. Lowering the minimum read capacity to 200 RCUs matches the actual consumption, preventing over-provisioning when auto scaling scales down. This reduces costs without affecting performance, as the capacity remains sufficient for the consistent workload. Option A is incorrect because increasing the minimum would raise costs unnecessarily. Option C is incorrect because disabling auto scaling removes the ability to handle traffic spikes automatically. Option D is incorrect because decreasing the maximum could cause throttling during unexpected demand spikes.

Answer

Increase the minimum read capacity to 500 RCUs.

Answer

Disable auto scaling and set the read capacity to 200 RCUs.

Answer

Decrease the maximum read capacity to 500 RCUs.

Question 14

A company is running an Amazon Redshift cluster with a single node. They need to improve query performance for large analytical workloads. Which action would provide the most immediate performance improvement?

Accepted Answer

Increase the number of nodes in the cluster.. Adding more nodes to the cluster distributes the workload and improves parallelism. Option A is wrong because using a single node, distributing data across slices is limited. Option B is wrong because compression is already used typically. Option D is wrong because VACUUM reclaims space but does not significantly improve performance for large workloads.

Answer

Distribute the data across all slices.

Answer

Apply compression encodings to all columns.

Answer

Run the VACUUM command to reclaim space.

Question 15

A company is using Amazon ElastiCache for Redis to cache database query results. The cache cluster is a single node. The application experiences increased latency when the cache misses. Which TWO actions can improve the cache hit ratio?

Accepted Answer

Increase the Time-to-Live (TTL) for cached items.. Options A and E are correct. Option A: Increasing TTL keeps data in cache longer, reducing cache misses. Option E: Implementing lazy loading populates the cache on read requests, improving hit ratio over time. Option B is wrong because disabling persistence does not affect cache hit ratio. Option C is wrong because decreasing TTL would increase cache misses. Option D is wrong because adding read replicas improves read throughput but does not improve cache hit ratio.

Answer

Disable persistence to free memory.

Answer

Decrease the Time-to-Live (TTL) for cached items.

Answer

Add read replicas to the ElastiCache cluster.