SOA-C02 Reliability and Business Continuity Practice Test 10 — 15 Questions

Question 1

A SysOps administrator is reviewing the reliability of a production system that uses Amazon DynamoDB as its primary data store. The table has on-demand capacity and a single partition key. The application experiences occasional throttling errors during peak hours. Which action would most effectively improve reliability?

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

Accepted Answer

Review and optimize the partition key design to avoid hot partitions.. Throttling errors in DynamoDB with a single partition key are most often caused by uneven access patterns creating hot partitions. Optimizing the partition key design (e.g., using a composite key or adding a suffix to distribute writes) directly addresses the root cause by ensuring requests are spread evenly across partitions, which on-demand capacity alone cannot fix. This improves reliability by preventing throttling at the partition level, regardless of the table's total capacity.

Answer

Switch to provisioned capacity and set high read/write units.

Answer

Enable auto-scaling and increase the maximum capacity.

Answer

Enable DynamoDB Accelerator (DAX) to reduce read latency.

Question 2

A company is designing a disaster recovery strategy for its AWS environment. The primary Region is us-east-1, and the secondary Region is us-west-2. The application uses Amazon RDS for MySQL, Amazon S3 for static assets, and EC2 instances in an Auto Scaling group. The RTO is 30 minutes, and the RPO is 15 minutes. Which TWO actions should the SysOps administrator take to meet these requirements? (Choose two.)

Accepted Answer

Configure a cross-Region read replica for the RDS instance in us-west-2.. A cross-Region read replica in us-west-2 can be promoted to a primary instance in under 30 minutes, and with binary log (binlog) replication it can achieve an RPO of 15 minutes or less. This allows the RDS database to be recovered with minimal data loss in the secondary Region, meeting both the RTO and RPO targets.

Answer

Deploy a single RDS instance in us-west-2 as a standby.

Answer

Create AMI backups of EC2 instances every hour and copy to us-west-2.

Answer

Take daily EBS snapshots and copy them to us-west-2.

Question 3

A SysOps administrator is responsible for an Auto Scaling group that runs a critical application. The administrator wants to ensure that the application can recover from an AZ failure. Which THREE steps should the administrator take? (Choose three.)

Accepted Answer

Place subnets in each Availability Zone used by the Auto Scaling group.. Placing subnets in each Availability Zone (AZ) used by the Auto Scaling group allows the group to launch EC2 instances in multiple AZs, which is essential for fault isolation. If one AZ fails, the Auto Scaling group can still launch and maintain instances in the other AZs, ensuring application availability. Without subnets in each AZ, the Auto Scaling group cannot distribute instances across AZs, defeating the purpose of high availability.

Answer

Use EC2 instances in a single Availability Zone to reduce latency.

Answer

Use a single subnet in one Availability Zone to simplify network design.

Question 4

A SysOps administrator wants to back up an Amazon EBS volume that is attached to an EC2 instance running a production database. The backup must be crash-consistent and should not cause any downtime. Which TWO steps should the administrator take? (Choose two.)

Accepted Answer

Take a snapshot of the EBS volume after freezing.. Taking a snapshot after freezing the filesystem ensures that the snapshot captures a crash-consistent state of the EBS volume. Option E is correct because using a tool like fsfreeze flushes all pending I/O operations and freezes the filesystem, which prevents data inconsistencies without stopping the EC2 instance or detaching the volume.

Answer

Stop the EC2 instance before taking the snapshot.

Answer

Take a snapshot directly from the attached volume without any preparation.

Answer

Detach the volume from the instance before taking a snapshot.

Question 5

A company runs a web application on EC2 instances behind an Application Load Balancer. The instances are in an Auto Scaling group across three Availability Zones. To improve reliability, the company wants to ensure that if an entire Availability Zone fails, the application remains available. Which configuration should be implemented?

Accepted Answer

Configure the Auto Scaling group to launch instances in three Availability Zones.. Configuring the Auto Scaling group to launch instances across three Availability Zones ensures that if one AZ fails, the remaining AZs continue to serve traffic. The Application Load Balancer automatically distributes incoming requests to healthy instances in the surviving AZs, maintaining application availability without manual intervention.

Answer

Remove the load balancer and use Route 53 weighted routing to distribute traffic.

Answer

Launch all instances in a single Availability Zone to reduce latency.

Answer

Use a Network Load Balancer instead of an Application Load Balancer.

Question 6

A SysOps administrator is designing a disaster recovery plan for a critical application hosted on AWS. The application runs on EC2 instances with data stored in an RDS MySQL database. The RPO must be less than 15 minutes, and the RTO must be less than 1 hour. Which solution meets these requirements?

Accepted Answer

Use an RDS Multi-AZ DB Cluster deployment.. An RDS Multi-AZ DB Cluster deployment provides synchronous replication across three Availability Zones and automatic failover, enabling an RTO of typically under 1 minute and an RPO of effectively zero (no data loss). This meets the strict RPO (<15 minutes) and RTO (<1 hour) requirements without relying on cross-Region replication or manual recovery steps.

Answer

Take daily snapshots of the RDS instance and copy them to another Region.

Answer

Use an RDS DB instance with a Multi-AZ standby and a cross-Region Read Replica.

Answer

Use a single-AZ RDS instance with automated backups and point-in-time recovery.

Question 7

A company has a production application running on Amazon ECS with Fargate launch type. The application uses an Application Load Balancer. The SysOps administrator notices that during deployments, the application experiences a brief period of downtime. Which combination of actions should the administrator take to achieve zero-downtime deployments?

Accepted Answer

Configure the ECS service to use a rolling update with a minimum healthy percent of 100 and a maximum percent of 200.. Setting the minimum healthy percent to 100 and maximum percent to 200 ensures that during a rolling update, the ECS service first launches new tasks (up to 200% of the desired count) before terminating any old tasks. This guarantees that the ALB always has a sufficient number of healthy targets to serve traffic, eliminating downtime. The Application Load Balancer distributes traffic between old and new tasks during the transition, achieving zero-downtime deployments.

Answer

Configure the ECS service to use a rolling update with a minimum healthy percent of 0 and a maximum percent of 100.

Answer

Increase the deregistration delay on the ALB target group to 300 seconds.

Answer

Use a blue/green deployment with CodeDeploy and set the 'Minimum healthy percent' to 50.

Question 8

A company stores critical data in an S3 bucket. To ensure data durability and availability, the company wants to automatically replicate objects to a bucket in a different AWS Region. Which S3 feature should be used?

Accepted Answer

Configure S3 Cross-Region Replication.. S3 Cross-Region Replication (CRR) is the correct feature because it automatically and asynchronously replicates objects from a source S3 bucket in one AWS Region to a destination bucket in a different AWS Region. This ensures data durability and availability by maintaining a copy in a separate geographic location, meeting the requirement for cross-region replication. CRR requires versioning to be enabled on both source and destination buckets.

Answer

Enable S3 Standard storage class on the bucket.

Answer

Use S3 One Zone-IA storage class.

Answer

Enable S3 Versioning on the bucket.

Question 9

An application runs on EC2 instances in an Auto Scaling group. The instances process messages from an SQS queue. To ensure high availability, the SysOps administrator has configured the Auto Scaling group to span three Availability Zones. However, during a recent failure of one AZ, the application experienced a temporary increase in processing latency. What is the MOST likely cause of this latency?

Accepted Answer

SQS messages in the failed AZ are temporarily unavailable until they are replicated to other AZs.. SQS stores messages redundantly across multiple AZs within a region, but when an AZ fails, messages that were in-flight or stored in that AZ become temporarily unavailable until the SQS service completes its internal replication and recovery processes. This transient unavailability causes a spike in processing latency because the application cannot retrieve those messages until they are replicated to healthy AZs. The latency resolves once SQS finishes replicating the messages to the remaining AZs.

Answer

The SQS queue is configured to use a single AZ for message storage.

Answer

The application is not configured to process messages from multiple AZs.

Answer

The Auto Scaling group's minimum size is too low to handle the load after the AZ failure.

Question 10

A company wants to ensure that its EC2 instances automatically recover from an instance failure. Which feature should be used?

Accepted Answer

Enable EC2 Auto Recovery on the instance.. EC2 Auto Recovery is a feature that automatically recovers an EC2 instance when it becomes impaired due to an underlying hardware or system issue. When enabled, CloudWatch monitors the instance's status checks and, upon detecting a failure, automatically stops and starts the instance on a new healthy host, preserving its private IP, Elastic IP, and instance metadata.

Answer

Create a CloudWatch alarm that sends an email when the instance status check fails.

Answer

Configure an Auto Scaling group with a launch configuration.

Answer

Attach the instance to an Elastic Load Balancer.

Question 11

A company runs a stateful web application on a single EC2 instance. To improve reliability, the company wants to implement a highly available architecture. What should the SysOps administrator do?

Accepted Answer

Refactor the application to store session state externally (e.g., ElastiCache), then deploy it across multiple AZs with an Application Load Balancer.. It addresses the core challenge of making a stateful web application highly available. By storing session state externally in ElastiCache, the application becomes stateless from a networking perspective, allowing any EC2 instance to handle any request. Deploying these instances across multiple Availability Zones (AZs) behind an Application Load Balancer (ALB) provides fault tolerance and automatic traffic distribution, eliminating the single point of failure.

Answer

Migrate the application to a larger instance type.

Answer

Create a standby EC2 instance and use an Elastic IP to fail over manually.

Answer

Use Route 53 health checks to route traffic to a secondary instance if the primary fails.

Question 12

A company uses Amazon Route 53 for DNS and wants to ensure that its web application is highly available across two AWS Regions. The application runs behind an Application Load Balancer in each Region. Which routing policy should be used?

Accepted Answer

Failover routing policy. The failover routing policy in Amazon Route 53 is designed to route traffic to a primary resource (e.g., an Application Load Balancer in one AWS Region) and automatically redirect to a secondary resource (e.g., an ALB in another Region) if the primary becomes unhealthy. This ensures high availability across two Regions by using health checks to detect failures and perform DNS failover, which directly meets the requirement for multi-Region redundancy.

Answer

Weighted routing policy

Answer

Geolocation routing policy

Answer

Latency routing policy

Question 13

A company runs a critical application on an EC2 instance backed by Amazon EBS. To protect against data loss, the company wants to create a backup strategy that allows for point-in-time recovery. Which solution should be used?

Accepted Answer

Create automated EBS snapshots.. Automated EBS snapshots provide point-in-time backups of the EBS volume, enabling granular recovery to a specific moment. Snapshots are stored in Amazon S3 and can be used to restore the volume or create new instances, directly addressing the requirement for point-in-time recovery against data loss.

Answer

Configure an S3 Lifecycle policy to move data to Glacier.

Answer

Create an Amazon Machine Image (AMI) of the instance.

Answer

Use Amazon EFS to store data.

Question 14

A company is designing a disaster recovery strategy for its production database hosted on Amazon RDS for MySQL. The primary database is in us-east-1. The company requires an RPO of less than 5 minutes and an RTO of less than 1 hour in the event of a Regional failure. Which TWO actions should the company take to meet these requirements?

Accepted Answer

Create a cross-Region Read Replica in us-west-2 and promote it during a disaster.. A cross-Region Read Replica in us-west-2 can be promoted to a standalone primary database during a disaster, enabling failover with an RTO typically under 1 hour. The replication lag is usually seconds to a few minutes, meeting the RPO of less than 5 minutes. This approach provides a warm standby in another Region without requiring manual snapshot restores.

Answer

Take daily manual snapshots and copy them to us-west-2.

Answer

Enable Multi-AZ deployment for the RDS instance.

Answer

Use a single-AZ RDS instance with automated backups.

Question 15

A company runs a web application on EC2 instances behind an Application Load Balancer. The instances are in an Auto Scaling group. The SysOps administrator wants to ensure that the application can handle a sudden increase in traffic without downtime. Which THREE actions should be taken?

Accepted Answer

Configure the Auto Scaling group to launch instances in multiple Availability Zones.. Launching instances in multiple Availability Zones (AZs) ensures high availability and fault tolerance. If one AZ experiences a failure, the Auto Scaling group can still serve traffic from instances in other AZs, preventing downtime during sudden traffic spikes or infrastructure issues.

Answer

Configure a scheduled scaling policy to add instances during known peak hours.

Answer

Use Spot Instances to reduce costs.