DBS-C01 Management and Operations Practice Test 10 — 15 Questions

Question 1

A company is migrating an on-premises Oracle database to Amazon RDS for Oracle. The database is 500 GB and has a 4-hour downtime window. Which AWS service should be used to perform the migration with minimal downtime?

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

Accepted Answer

AWS Database Migration Service (DMS). AWS Database Migration Service (DMS) is the correct choice because it supports ongoing replication (change data capture) to minimize downtime during the migration. Oracle Data Pump is an export/import tool that requires downtime and cannot perform continuous replication. AWS Snowball Edge is for offline bulk data transfer, not suitable for a 4-hour window with minimal downtime. Amazon S3 Transfer Acceleration only speeds up uploads to S3, not a database migration tool. Therefore, DMS is the recommended service for minimal downtime migration.

Answer

Oracle Data Pump using Amazon RDS option groups

Answer

AWS Snowball Edge

Answer

Amazon S3 Transfer Acceleration

Question 2

A company has an Amazon Redshift cluster that is running slowly on complex queries. The cluster has 10 dc2.large nodes. The 'QueryDuration' metric shows high values for several queries. The team wants to improve performance without changing queries. Which action is MOST likely to help?

Accepted Answer

Add more nodes of the same type to the cluster.. Adding more nodes (scaling out) increases the cluster's compute capacity, allowing complex queries to process data in parallel without any query changes. Option C is incorrect because Redshift Spectrum requires data to be in S3 and external tables to be defined, which would require modifying queries to reference those tables. Option B reduces storage I/O but not CPU-bound complex queries. Option D increasing concurrency can cause resource contention, slowing queries.

Answer

Enable compression on all columns.

Answer

Enable Redshift Spectrum to offload queries to Amazon S3.

Answer

Increase the workload management (WLM) concurrency level.

Question 3

A company runs a critical Amazon RDS for PostgreSQL database. They notice that the 'DiskQueueDepth' metric is consistently high and the 'FreeStorageSpace' is below 10%. The database is used for OLTP workloads. What is the MOST immediate action to take?

Accepted Answer

Modify the DB instance to increase allocated storage.. Increasing allocated storage quickly addresses the low free storage space (below 10%) and high DiskQueueDepth, which indicates I/O bottlenecks due to insufficient storage. Option A is wrong because upgrading to a larger instance class improves memory and CPU but does not directly resolve storage shortage or I/O throttling caused by low disk space. Option C is wrong because switching to Provisioned IOPS improves latency and throughput but does not increase storage capacity. Option D is wrong because creating a read replica offloads read traffic but does not increase storage on the primary instance.

Answer

Upgrade to a larger DB instance class.

Answer

Switch the instance to Provisioned IOPS storage.

Answer

Create a read replica to offload read traffic.

Question 4

A company needs to audit all SQL queries executed on an Amazon RDS for SQL Server database. Which AWS service should be used?

Accepted Answer

Amazon RDS Database Activity Streams. Amazon RDS Database Activity Streams provides a near real-time feed of database activity, including SQL queries, making it ideal for auditing all SQL queries on an RDS for SQL Server database. AWS CloudTrail (Option D) logs API calls to AWS services, not SQL queries. VPC Flow Logs (Option B) capture network traffic metadata, not database queries. Amazon CloudWatch Logs (Option C) can store and monitor logs but requires a log source; RDS does not natively send SQL logs to CloudWatch unless integrated with Database Activity Streams, which is the direct solution. Therefore, Option A is correct.

Answer

Amazon VPC Flow Logs

Answer

Amazon CloudWatch Logs

Answer

AWS CloudTrail

Question 5

A company is using Amazon ElastiCache for Redis to cache database query results. They notice that the cache hit ratio is low and many requests are hitting the database. The 'Evictions' metric is high. What is the MOST likely cause?

Accepted Answer

The cache node is too small for the workload.. The high 'Evictions' metric indicates that the cache node is constantly full, causing it to evict old data to make room for new data. This leads to a low cache hit ratio because frequently accessed items are evicted and must be fetched from the database. Option D correctly identifies that the cache node is too small for the workload. Option A is incorrect because insufficient replication factor would affect availability, not evictions. Option B is incorrect because encryption in transit does not impact cache capacity or evictions. Option C is incorrect because high network latency would affect request latency but not directly cause evictions.

Answer

The replication factor is insufficient.

Answer

Encryption in transit is enabled.

Answer

The application is experiencing high network latency.

Question 6

A company is running an Amazon DynamoDB table with global secondary indexes (GSIs). Write activity increases, and the 'ThrottledWriteEvents' metric for a GSI spikes. The table itself is not throttled. What is the most likely cause?

Accepted Answer

The GSI's partition key is not sufficiently distributed.. Write sharding on the GSI partition key can cause hot partitions. Option A is wrong because read capacity on the GSI does not affect writes. Option C is wrong because write capacity on the table is separate from GSI. Option D is wrong because the issue is about throttling on GSI, not table.

Answer

The index is too large for the base table.

Answer

The table's write capacity is set too low.

Answer

The GSI's read capacity is set too low.

Question 7

A company wants to automate backups for an Amazon RDS for PostgreSQL DB instance. The backup retention period should be 35 days. Which step is required?

Accepted Answer

Enable automated backups with a retention period of 35 days.. Amazon RDS for PostgreSQL supports automated backups with a configurable retention period of up to 35 days. By enabling automated backups and setting the retention period to 35 days, the company meets the requirement without additional tooling or manual effort. Automated backups include transaction logs for point-in-time recovery, which is not available with manual snapshots alone.

Answer

Use AWS Backup to schedule backups.

Answer

Create a manual snapshot every day and delete after 35 days.

Answer

Set up a cross-region snapshot copy.

Question 8

A company is designing a disaster recovery plan for an Amazon RDS for MySQL database. The database must have a Recovery Point Objective (RPO) of less than 5 minutes and a Recovery Time Objective (RTO) of less than 1 hour. Which TWO actions should be taken? (Choose two.)

Accepted Answer

Deploy the database in a Multi-AZ configuration.. (Multi-AZ configuration) provides automatic synchronous replication to a standby instance in a different Availability Zone. In the event of a failure, automatic failover occurs within minutes, achieving an RTO of less than 1 hour and an RPO of effectively zero. Option C (cross-region read replica with automated backups enabled) replicates data asynchronously to another AWS region, allowing promotion to a standalone database for disaster recovery. With continuous replication, the RPO can be less than 5 minutes, and promotion time is typically under 1 hour, meeting both objectives.

Option A is incorrect because a single-AZ instance with automated backups requires restoring from a backup, which takes longer than 1 hour, failing the RTO requirement. Option D is incorrect because daily manual snapshots have an RPO of up to 24 hours, exceeding the 5-minute requirement. Option E is incorrect because AWS DMS is primarily a migration service and is not optimized for continuous replication for DR; it adds complexity and does not provide the same RTO/RPO guarantees as native RDS replication features.

Answer

Use a single-AZ instance with automated backups to S3.

Answer

Take daily manual snapshots and copy them to another region.

Answer

Use AWS DMS for continuous replication to a standby instance.

Question 9

A company is migrating an on-premises MongoDB database to Amazon DocumentDB. The migration must have minimal downtime. Which THREE steps should be taken? (Choose three.)

Accepted Answer

Create an Amazon DocumentDB cluster as the target.. You must create the target DocumentDB cluster before migration. Option C is correct: AWS DMS can perform a full load followed by ongoing replication to minimize downtime. Option E is correct: the source MongoDB must be configured to capture oplog events so that DMS can replicate changes. Option A is incorrect because AWS Snowball Edge is for offline data transfer, which would not achieve minimal downtime. Option D is incorrect because sharding the cluster across multiple regions is not required for a migration with minimal downtime.

Answer

Use AWS Snowball Edge to transfer initial data.

Answer

Shard the DocumentDB cluster across multiple regions.

Question 10

A company is using Amazon RDS for Oracle with Automated Backups enabled. The database size is 1 TB. The company wants to improve the backup and restore performance. Which TWO actions should be taken? (Choose two.)

Accepted Answer

Use Provisioned IOPS storage for the database.. Using Provisioned IOPS storage improves I/O performance, which speeds up backup and restore operations. Option B is correct because enabling backup compression reduces the backup size, leading to faster transfer and restore times. Option C is wrong because using a smaller DB instance class would degrade performance, not improve it. Option D is wrong because increasing the backup retention period to 35 days does not affect backup performance; it only increases the storage used. Option E is wrong because disabling Multi-AZ would reduce availability and does not improve backup performance; in fact, Multi-AZ can improve backup performance by offloading backups to the standby instance.

Answer

Use a smaller DB instance class to reduce backup size.

Answer

Increase the backup retention period to 35 days.

Answer

Disable Multi-AZ to reduce backup time.

Question 11

A company runs a critical e-commerce application on Amazon RDS for MySQL with Multi-AZ enabled. The database is 2 TB and uses General Purpose (gp2) storage. Recently, during peak hours, the application experienced a 5-minute outage. The CloudWatch logs show that the primary DB instance failed and an automatic failover occurred. However, the failover took 3 minutes, which is longer than the expected 1-2 minutes. The 'ReadLatency' and 'WriteLatency' metrics were elevated before the failure. The 'BurstBalance' metric was at 0% for the hour before the failure. The team suspects the issue is related to storage performance. What should the team do to prevent this issue in the future?

Accepted Answer

Change the storage type to Provisioned IOPS (io1).. The BurstBalance at 0% indicates the gp2 volume exhausted its burst credits, causing I/O throttling and increased latency, which likely contributed to the failover delay. Switching to Provisioned IOPS (io1) provides consistent performance and avoids burst credit exhaustion. Option A is wrong because increasing the DB instance class addresses compute capacity, not storage I/O. Option C is wrong because backup retention period does not affect storage performance. Option D is wrong because read replicas offload read traffic but do not improve write performance on the primary instance.

Answer

Increase the DB instance class to a larger size.

Answer

Increase the backup retention period to 35 days.

Answer

Create a read replica to offload read traffic.

Question 12

A company uses Amazon DynamoDB for a real-time analytics application. The table is provisioned with 1000 RCU and 500 WCU. Recently, the application experienced throttling on reads during a marketing campaign. The 'ConsumedReadCapacityUnits' metric shows spikes up to 2000 RCU. The 'ReadThrottleEvents' metric is high. The table has a global secondary index (GSI) that is also throttled. The application uses eventually consistent reads. The team wants to minimize costs while preventing throttling. The campaign traffic is predictable and occurs for 2 hours each day. What should the team do?

Accepted Answer

Enable auto scaling with a scheduled scaling action to increase RCU during the campaign.. The traffic is predictable and occurs for 2 hours daily. Scheduled auto scaling can increase RCU during the campaign and reduce it afterward, minimizing cost while preventing throttling. Option A is incorrect because permanently increasing RCU to 2000 would waste capacity during the other 22 hours, increasing costs unnecessarily. Option B is incorrect because DynamoDB Accelerator (DAX) adds cost and primarily caches base table reads, not global secondary index reads; the GSI is also throttled, so DAX may not fully resolve the issue, and scheduled scaling is more cost-effective for predictable patterns. Option D is incorrect because on-demand capacity mode is more expensive for predictable, sustained high traffic; auto scaling with a schedule is cheaper for this use case.

Answer

Increase the provisioned RCU to 2000 permanently.

Answer

Implement DynamoDB Accelerator (DAX) to cache reads.

Answer

Switch the table to on-demand capacity mode.

Question 13

A company recently migrated an on-premises PostgreSQL database to Amazon RDS for PostgreSQL. The database is 100 GB and used by a web application. After migration, the application's response time increased. The 'ReadLatency' and 'WriteLatency' metrics are normal. The 'CPUUtilization' is at 90%. The 'DatabaseConnections' metric shows 200 connections, which is close to the max connections for the instance class (db.t3.medium, max connections = 200). The application uses connection pooling. The team wants to reduce CPU utilization without changing the application code. Which action should the team take?

Accepted Answer

Upgrade the DB instance to a larger class like db.t3.large.. Upgrading to a larger instance class, such as db.t3.large, provides more CPU resources (additional vCPUs), directly addressing the high CPU utilization (90%) while maintaining the same number of database connections. Option A is incorrect because decreasing 'max_connections' to 100 risks rejecting legitimate connections from the application's connection pool, potentially causing errors even though connection pooling is in use. Option B is incorrect because increasing allocated storage improves I/O throughput but does not reduce CPU utilization; the I/O latency metrics are already normal. Option D is incorrect because enabling Performance Insights adds monitoring overhead and switching to Provisioned IOPS improves I/O performance, but the bottleneck is CPU, not I/O.

Answer

Decrease 'max_connections' parameter to 100.

Answer

Increase allocated storage to 200 GB.

Answer

Enable Performance Insights and switch to Provisioned IOPS.

Question 14

A company runs a production Amazon RDS for MySQL Multi-AZ DB instance. The database experiences a failover event. After the failover, the application team reports increased latency for write operations. Which action should be taken to investigate the issue?

Accepted Answer

Verify that the application is using the correct DB endpoint and that DNS has propagated.. After a failover, the DNS record updates to point to the new primary. If DNS has not propagated, the application may be connecting to the old primary or experiencing routing issues, leading to increased write latency. Verifying DNS resolution ensures the application is using the correct endpoint.

Option A is incorrect because increasing storage does not directly address latency caused by DNS propagation; it might help with I/O contention under normal conditions, but it is not the appropriate first step for investigating post-failover latency.

Option B is incorrect because automated backups do not impact write latency; they run in the background and do not interfere with database operations.

Option D is incorrect because changing the instance class can improve performance, but the immediate issue after failover is likely DNS propagation, not insufficient compute capacity.

Answer

Increase the allocated storage for the DB instance to reduce I/O contention.

Answer

Enable automated backups and configure a backup window.

Answer

Modify the DB instance to a larger instance class to improve write performance.

Question 15

A company uses Amazon DynamoDB to store session data for a web application. The application is experiencing occasional throttling (ProvisionedThroughputExceededException) during peak hours. The DynamoDB table has on-demand capacity mode. Which combination of steps should be taken to resolve the issue?

Accepted Answer

Review the partition key design and consider using a write sharding pattern to distribute traffic evenly.. Even with on-demand capacity, DynamoDB applies a per-partition throughput limit (3,000 RCU or 1,000 WCU). Throttling occurs when traffic is unevenly distributed across partitions due to a suboptimal partition key. Reviewing the partition key and applying a write sharding pattern (e.g., adding a random suffix) distributes writes evenly, preventing throttling. Option B (DAX) only reduces read load and does not fix write throttling. Option C (auto scaling) is for provisioned mode, not on-demand. Option D (switching to provisioned) does not resolve uneven partition access; proper key design is still needed.

Answer

Enable DynamoDB Accelerator (DAX) to cache the frequently accessed items.

Answer

Enable auto scaling for the table and set minimum and maximum capacity.

Answer

Switch to provisioned capacity and increase the read and write capacity units.