Question 1hardmultiple choice
Full question →hardmultiple choiceObjective-mapped
A company runs a read-heavy database workload on Amazon RDS for PostgreSQL with a primary instance and two read replicas. The SysOps administrator observes that the read replicas frequently experience high replica lag during peak hours, causing stale reads for the application. The administrator needs to reduce replica lag while optimizing costs. The workload is predictable, with spikes during business hours and low traffic at night. Which combination of actions should the administrator take?
Answer choices
Why each option matters
Good practice is not just finding the correct option. The wrong answers often show the exact trap the exam wants you to fall into.
A
Distractor review
Convert the read replicas to Multi-AZ instances to improve the replication process and reduce lag.
Multi-AZ for read replicas provides standby replicas for failover, but it does not reduce replica lag. In fact, running Multi-AZ adds overhead because the primary in the replica's AZ must also replicate to the standby.
B
Best answer
Upgrade the instance class of the read replicas to a larger type with more CPU and memory to handle the increased WAL replay rate.
Replica lag occurs when the replica cannot keep up with the rate of changes from the primary. Increasing the replica's instance size gives it more resources to apply WAL data faster, reducing lag. This directly addresses the performance bottleneck.
C
Distractor review
Add additional read replicas to distribute the read load and reduce the lag on each individual replica.
Adding more replicas does not reduce the lag on existing replicas; it may increase the load on the primary because it must stream the WAL to more replicas, potentially worsening the lag. The solution is to make each replica more powerful.
D
Distractor review
Upgrade the primary DB instance to a larger class with increased IOPS to reduce the amount of data that needs to be replicated.
While upgrading the primary could improve overall throughput, the replica lag is specifically caused by the replicas' inability to apply changes quickly. The replicas are the bottleneck. Upgrading the primary is less cost-effective and may not solve the lag issue.
Common exam trap
Common exam trap: NAT rules depend on direction and matching traffic
NAT is not only about the public address. The inside/outside interface roles and the ACL or rule that matches traffic are just as important.
Technical deep dive
How to think about this question
NAT questions usually test address translation, overload/PAT behaviour, static mappings and whether the right traffic is being translated. Read the interface direction and address terms carefully.
KKey Concepts to Remember
- Static NAT maps one inside address to one outside address.
- PAT allows many inside hosts to share one public address using ports.
- Inside local and inside global describe the private and translated addresses.
- NAT ACLs identify traffic for translation, not always security filtering.
TExam Day Tips
- Identify inside and outside interfaces first.
- Check whether the scenario needs static NAT, dynamic NAT or PAT.
- Do not confuse NAT matching ACLs with normal packet-filtering intent.
Related practice questions
Related SOA-C02 practice-question pages
Use these pages to review the topic behind this question. This is how one missed question becomes focused revision.
More questions from this exam
Keep practising from the same exam bank, or move into a focused topic page if this question exposed a weak area.
Question 1
A company uses Amazon CloudFront to deliver content to a global audience. The origin is an Application Load Balancer in us-east-1. The SysOps administrator wants to reduce costs by minimizing the number of requests that reach the origin server. Which action should the administrator take?
Question 2
A company runs a batch processing application on Amazon EC2 that runs for 2 hours every night. The workload can tolerate interruptions. Which EC2 purchasing option provides the lowest cost for this use case?
Question 3
A SysOps administrator needs to monitor the CPU utilization of an Amazon RDS DB instance and receive an alarm when CPU utilization exceeds 80% for 5 consecutive minutes. Which AWS service should be used to create this alarm?
Question 4
A company runs a critical web application on Amazon EC2 instances in an Auto Scaling group behind an Application Load Balancer (ALB). The application uses session stickiness (sticky sessions) to maintain user sessions. The SysOps administrator notices that when instances are replaced during a scale-in or failure event, users lose their session data. The administrator needs to preserve session data across instance failures without losing stickiness benefits. What should the administrator do?
Question 5
A company runs a production web application on a single Amazon EC2 instance. The application experiences a predictable and steady workload 24/7. The SysOps administrator wants to minimize compute costs for this instance while ensuring it remains available during the expected workload. Which EC2 purchasing option should the administrator use?
Question 6
A company has a VPC with public and private subnets. The private subnets host application servers that need to make outbound HTTPS connections to the internet. The SysOps administrator must implement a solution that provides outbound internet connectivity while preventing inbound connections from the internet. Additionally, the solution must allow the company to control which domains the application servers can access. Which solution should the administrator implement?
FAQ
Questions learners often ask
What does this SOA-C02 question test?
Static NAT maps one inside address to one outside address.
What is the correct answer to this question?
The correct answer is: Upgrade the instance class of the read replicas to a larger type with more CPU and memory to handle the increased WAL replay rate. — Reducing replica lag typically requires more CPU and memory on the replicas to process the write-ahead log (WAL) from the primary faster. Upgrading the read replicas to a larger instance class with more compute resources will reduce lag. Additionally, using a multi-AZ deployment for the read replicas does not reduce lag; it improves durability. Option A is not optimal because Multi-AZ for replicas is for availability, not performance. Option C adds more replicas, which may help distribute the read load but does not directly reduce the lag of each replica; it could even increase lag on the primary due to additional replication streams. Option D is costly because upgrading the primary might not be necessary if the primary has sufficient capacity; the bottleneck is on the replicas.
What should I do if I get this SOA-C02 question wrong?
Then try more questions from the same exam bank and focus on understanding why the wrong options are tempting.
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