SOA-C02 Cost and Performance Optimization Practice Question

A SysOps administrator needs to reduce costs for a non-production environment that runs 24/7 but is only used during business hours. What is the MOST effective action?

⚠ Common exam trap

SOA-C02 often tests the difference between cost-saving measures that reduce usage versus those that reduce rates; candidates may choose Reserved Instances or Spot, but stopping instances is most effective for intermittent usage.

Answer choices

Why each option matters

Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.

Correct answer & explanation

✓

Create a schedule to stop instances after business hours and start them before.

Creating a schedule to stop instances after business hours and start them before business hours is the most effective cost-saving action because it directly reduces the hours the instances run, which is the primary cost driver for EC2. Since the environment is only used during business hours, stopping instances during off-hours eliminates unnecessary compute charges. This approach is simple, requires no architectural changes, and yields immediate savings.

Answer analysis

Option-by-option breakdown

For each option: why learners choose it and why it is or isn't the right answer here.

✓
Create a schedule to stop instances after business hours and start them before.
Why this is correct
Stopping EC2 instances outside of business hours eliminates per-second compute charges while they are in the stopped state, while EBS volumes and their data persist. You can use AWS Instance Scheduler or Systems Manager Automation to codify the start/stop routine, ensuring instances are only running when needed. This approach directly targets idle compute waste without deprovisioning the environment.
✗
Switch all instances to Spot Instances.
Why it's wrong here
Spot Instances offer discounted prices but are interruptible—AWS can reclaim them with two minutes of notice when capacity is constrained or demand spikes. They are suitable for stateless, fault-tolerant workloads, not for a general-purpose non-production environment that must be predictably available each day. Converting all instances to Spot would risk sudden downtime during business hours, and a scheduled stop/start pattern does not align with Spot's lifecycle.
✗
Purchase Reserved Instances for the environment.
Why it's wrong here
Reserved Instances require a 1- or 3-year commitment to a specific instance family and region in exchange for a discount, but that discount is charged 24/7 regardless of actual usage. If the environment runs only during business hours, you are paying for idle capacity overnight and on weekends, making the effective cost per running hour higher. More importantly, RIs do not stop instances, so they fail to solve the root problem of instances remaining powered on outside peak time.
✗
Reduce the instance sizes to the smallest available.
Why it's wrong here
Choosing the smallest available instance size reduces the per-hour compute rate, but it does so at the risk of under-provisioning CPU, memory, and network. Even a tiny instance continues to incur compute charges around the clock, so it fails to eliminate the wasteful idle-time billing. Rightsizing only lowers the cost per hour; it does not address the 16 hours per day when the environment is not generating value.

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SOA-C02 Cost and Performance Optimization Practice Question

Why each option matters

Option-by-option breakdown

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