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

Question 1

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.. On-demand tables have a per-table throughput limit that can be exceeded, especially during a flash sale. Option A (WCU limit) does not apply to on-demand. Option B (partition hot spot) could cause throttling even in on-demand if a single partition is overloaded. Option C (table limit) is correct, but partition hot spots are a common cause. The best answer is B because on-demand automatically scales but can still throttle if a partition is hot.

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 2

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. RDS provides the ReplicaLag metric in CloudWatch for PostgreSQL read replicas. Option A (DiskQueueDepth) is for storage. Option B (ReadLatency) is for read operations. Option D (TransactionLogsDiskUsage) is not a standard metric.

Answer

DiskQueueDepth

Answer

TransactionLogsDiskUsage

Answer

ReadLatency

Question 3

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 stores 6 copies of data across 3 AZs. The loss of two copies can be tolerated if they are distributed. Option A (3 copies in 3 AZs) is incorrect; Aurora uses 6 copies. Option B (2 copies in 2 AZs) is not correct. Option D (3 copies in 2 AZs) is not standard. The correct answer is C because Aurora's architecture provides higher durability.

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 4

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.. A local secondary index (LSI) on score allows efficient sorting within a partition. A global secondary index (GSI) on score would not be efficient for per-player queries. The correct options are A and D. Option B (GSI) would not help per-player sorting. Option C (scan) is inefficient. Option E (LSI on timestamp) is already present.

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 5

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. AWS RDS is the target, not a migration service. AWS DataSync is for file data, not databases. The correct options are B and D.

Answer

AWS DataSync

Answer

AWS Snowball

Answer

Amazon RDS for Oracle

Question 6

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 retention period of 35 days provide point-in-time recovery. Cross-region snapshots via AWS Backup provide additional protection. A read replica can be promoted quickly for failover. Option A (daily manual snapshots) may not meet the 5-minute RPO. Option D (single-AZ) is not as resilient. The correct options are B, C, and E.

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 7

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.. Option B is correct because adding a read replica offloads read traffic from the primary instance, reducing latency. Option A is wrong because Multi-AZ is for high availability, not read scaling. Option C is wrong because increasing storage size may improve IOPS but does not directly address read load. Option D is wrong because enabling Performance Insights is for monitoring, not performance improvement.

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 8

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:*".. Option C is correct because 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 9

A database specialist is configuring an Amazon RDS for PostgreSQL instance with automated backups enabled. The backup retention period is set to 7 days. The instance experiences a failure and becomes unavailable. What is the maximum amount of time the specialist has to recover the database to the most recent possible point in time?

Accepted Answer

7 days. Option C is correct because with automated backups and a retention period of 7 days, the latest restorable time is typically within the last 5 minutes, but the maximum point-in-time recovery window is 7 days. Option A is wrong because it is too short. Option B is wrong because it is the backup window, not recovery window. Option D is wrong because it exceeds the retention period.

Answer

1 hour

Answer

14 days

Answer

35 minutes

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 B and D are correct. Option B: Pre-creating a global table can distribute write traffic across regions, reducing load on a single table. Option D: Using DynamoDB Accelerator (DAX) can offload read traffic, reducing read capacity consumption. Option A is wrong because switching to provisioned capacity requires capacity planning but does not automatically prevent throttling. Option C is wrong because increasing read capacity units is not applicable to on-demand mode. Option E is wrong because decreasing write capacity is counterproductive.

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 THREE services or features should the specialist use to accomplish this?

Accepted Answer

An AWS DMS replication instance.. Options A, B, and D are correct. Option A: AWS DMS can perform ongoing replication with change data capture. Option B: AWS SCT helps convert the schema. Option D: A replication instance is required for DMS. Option C is wrong because RDS Oracle does not support cross-region automated backups as a migration tool. Option E is wrong because RDS Oracle does not support native Oracle Data Guard for cross-region replication.

Answer

Oracle Data Guard to replicate to RDS.

Answer

Amazon RDS cross-Region automated backups.

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.. Option B is correct because Multi-AZ failover can cause transient connection timeouts if the application does not have proper retry logic. Option A is wrong because the instance status is 'available', not 'storage-full'. Option C is wrong because MySQL 8.0.28 is a supported version. Option D is wrong because the instance class is db.r5.xlarge, which is a current generation instance.

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.. Option A is correct because lowering the minimum to 200 RCUs ensures auto scaling does not scale below the actual usage, reducing provisioned capacity costs. Option B is wrong because decreasing the maximum could cause throttling during spikes. Option C is wrong because increasing the minimum would increase costs unnecessarily. Option D is wrong because disabling auto scaling would require manual management and may lead to over-provisioning.

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.. Option C is correct because 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 the TTL keeps data in cache longer, reducing misses. Option E: Using lazy loading caches data on demand, which can improve hit ratio over time. Option B is wrong because decreasing TTL would increase misses. Option C is wrong because more read replicas do not improve hit ratio; they improve read throughput. Option D is wrong because disabling persistence does not affect 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.