SOA-C02 Reliability and Business Continuity Practice Test 12 — 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?

Accepted Answer

Review and optimize the partition key design to avoid hot partitions.. Option A is correct: On-demand capacity automatically scales to handle traffic spikes, but if the partition key design causes hot partitions, throttling can still occur. The most effective solution is to optimize the partition key to distribute workload evenly. Option B is incorrect because waiting for auto-scaling may not address hot partitions. Option C is incorrect because increasing read/write capacity in provisioned mode is a manual process and may not solve hot partition issues. Option D is incorrect because DAX is a caching layer that reduces read load but does not help with write throttling or hot partitions.

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.. Options A and D are correct. A cross-Region read replica in us-west-2 can be promoted to a primary in case of disaster, providing an RPO of seconds and RTO of minutes. S3 cross-Region replication ensures assets are available in the secondary Region with minimal RPO. Option B is incorrect because EBS snapshots are incremental and copying a snapshot would not meet RPO of 15 minutes if done daily. Option C is incorrect because AMI backups are for EC2 instances, not for database recovery. Option E is incorrect because a single RDS instance does not provide cross-Region failover.

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.. Options A, B, and D are correct. Launching instances in multiple AZs ensures that if one AZ fails, instances in other AZs continue. Distributing subnets across AZs is necessary for that. Using an ALB in multiple AZs distributes traffic. Option C is incorrect because a single subnet in one AZ does not provide AZ-level redundancy. Option E is incorrect because using only one AZ defeats the purpose.

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.. Options B and D are correct. To ensure crash consistency, the database should be frozen (e.g., via fsync) and I/O paused. Then take a snapshot of the volume. Option A is incorrect because taking a snapshot of a running volume without freezing may result in an inconsistent backup. Option C is incorrect because stopping the instance causes downtime. Option E is incorrect because detaching the volume causes downtime.

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.. Option A is correct because distributing the Auto Scaling group across three Availability Zones ensures that the application can tolerate the failure of one zone. Option B is wrong because using a single AZ would not survive an AZ failure. Option C is wrong because a Network Load Balancer does not inherently provide better zone resilience. Option D is wrong because removing the load balancer would remove a critical component for distributing traffic.

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.. Option D is correct because Multi-AZ DB Cluster provides automatic failover with low RPO and RTO, and synchronous replication keeps data consistent. Option A is wrong because single-AZ with snapshots has an RPO of up to 5 minutes and RTO of several hours. Option B is wrong because Read Replicas are asynchronous, leading to potential data loss. Option C is wrong because Daily snapshots do not meet the 15-minute RPO.

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.. Option C is correct because configuring the ECS service to use rolling updates with a minimum healthy percent of 100 and a maximum percent of 200 ensures that new tasks are started before old ones are stopped, avoiding downtime. Option A is wrong because it limits the number of new tasks. Option B is wrong because it stops old tasks first. Option D is wrong because deregistration delay alone does not prevent downtime during deployment.

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.. Option B is correct because S3 Cross-Region Replication (CRR) automatically replicates objects to a bucket in another Region. Option A is wrong because S3 Standard provides high durability but not automatic cross-region replication. Option C is wrong because S3 One Zone-IA does not replicate to another region. Option D is wrong because S3 Versioning is needed for CRR but does not itself replicate objects.

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.. Option D is correct because the SQS queue is a regional service, but the messages are distributed across AZs. When one AZ fails, messages in that AZ may become temporarily unavailable until they are replicated, causing a delay in processing. Option A is wrong because the Auto Scaling group is already configured to span three AZs. Option B is wrong because SQS automatically replicates across AZs. Option C is wrong because the application should be able to process messages from 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.. Option B is correct because EC2 Auto Recovery automatically recovers an instance if it becomes impaired due to an underlying hardware failure. Option A is wrong because EC2 Auto Scaling replaces instances based on scaling policies, not for individual instance failures. Option C is wrong because Elastic Load Balancing distributes traffic, it does not recover instances. Option D is wrong because CloudWatch alarms can trigger actions but not directly recover an instance by themselves.

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.. Option C is correct because making the application stateless and distributing instances across multiple AZs with a load balancer provides high availability. Option A is wrong because a larger instance is still a single point of failure. Option B is wrong because a standby instance is not automatically used; failover is manual. Option D is wrong because Route 53 health checks alone do not handle failover automatically if the instance is stateful.

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. Option D is correct because the failover routing policy allows you to configure an active-passive setup with health checks, routing traffic to the secondary Region only if the primary fails. Option A is wrong because weighted routing distributes traffic based on weights, not for failover. Option B is wrong because latency-based routing routes based on lowest latency, not failover. Option C is wrong because geolocation routing routes based on user location, not for failover.

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.. Option B is correct because Amazon EBS snapshots provide point-in-time backups of EBS volumes, stored in S3. Option A is wrong because S3 lifecycle policies do not back up EBS volumes. Option C is wrong because AMIs include snapshots but are not the primary backup mechanism for data. Option D is wrong because EFS is a file system, not a backup service.

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.. Options B and D are correct. Enabling cross-Region automated backups (Option B) provides continuous backup to another Region with low RPO. Option D, creating a cross-Region Read Replica and promoting it, allows fast failover with low RTO. Option A (Multi-AZ) is for AZ-level failure, not regional. Option C (snapshots) has higher RPO. Option E (single-AZ) does not provide failover.

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.. Options B, C, and E are correct. Configuring the Auto Scaling group with a dynamic scaling policy (Option B) allows it to scale based on demand. Placing instances in multiple Availability Zones (Option C) provides high availability. Configuring a target tracking scaling policy based on ALB RequestCountPerTarget (Option E) ensures the group scales based on traffic. Option A (scheduled scaling) is not reactive. Option D (spot instances) can be interrupted, causing potential downtime.

Answer

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

Answer

Use Spot Instances to reduce costs.