SAP-C02 Continuous Improvement for Existing Solutions Practice Question
A company wants to reduce costs for a batch processing workload that runs nightly on Amazon EMR. The workload is fault-tolerant and can handle interruptions. Which TWO strategies should they implement? (Choose TWO.)
⚠ Common exam trap
SAP-C02 often tests the misconception that Reserved Instances are always cost-saving, but for intermittent workloads like nightly batch, Spot Instances and right-sizing are more effective; candidates may overlook that task nodes are fault-tolerant.
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
✓
Right-size the cluster by analyzing resource utilization metrics.
Option B is correct because right-sizing the cluster based on CloudWatch resource utilization metrics (such as CPU, memory, and disk I/O) eliminates over-provisioned nodes, directly lowering EMR costs for a nightly batch workload. Option E is correct because Spot Instances can be used for task nodes in EMR, and since the workload is fault-tolerant and interruption-tolerant, the steep Spot discounts (up to ~90% off On-Demand) reduce costs substantially without risking data loss on core/HDFS nodes. Option A is wrong because On-Demand Instances for all nodes is the most expensive purchasing model and ignores the workload's tolerance for interruption. Option C is wrong because Reserved Instances require a 1- or 3-year commitment and are better suited to steady-state, predictable usage rather than a nightly batch job that may not run continuously. Option D is wrong because Dedicated Instances address tenancy/compliance requirements and typically cost more; they do not improve performance or reduce cost for this scenario.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
Use On-Demand Instances for all nodes.
Why it's wrong here
On-Demand pricing is the most expensive option and ignores the workload's fault tolerance, which is precisely what makes Spot viable. Spot Instances and Spot-based instance fleets cut EMR costs substantially. On-Demand would be chosen only where interruptions are unacceptable, such as a stateful, non-recoverable job.
- ✓
Right-size the cluster by analyzing resource utilization metrics.
Why this is correct
Right-sizing analyses CloudWatch metrics such as CPU, memory and HDFS utilisation to select appropriate instance types and task-node counts, eliminating over-provisioned capacity. Since the workload is fault-tolerant, smaller correctly sized clusters cut nightly EMR costs without affecting completion.
- ✗
Purchase Reserved Instances for the cluster.
Why it's wrong here
Reserved Instances suit steady, predictable, always-on capacity, not a nightly batch cluster whose nodes terminate after each run. They also cannot absorb interruption-friendly spot capacity. Spot Instances and instance fleets with Spot allocation are the cost-reduction strategies for fault-tolerant, interruptible EMR workloads.
- ✗
Use Dedicated Instances to improve performance.
Why it's wrong here
Dedicated Instances address tenancy and compliance isolation, not cost; they carry a premium over shared tenancy and do nothing for a fault-tolerant batch job. Spot Instances and Spot instance fleets are the correct cost levers. Dedicated tenancy would be chosen for regulatory or licensing isolation requirements.
- ✓
Use Spot Instances for task nodes.
Why this is correct
Task nodes handle only map and reduce work and hold no HDFS data, so Spot interruptions cause no data loss on a fault-tolerant nightly job. Spot capacity costs substantially less than On-Demand, directly reducing EMR spend while the workload's interruption tolerance satisfies the stem's constraint.
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Same concept, more angles
1 more way this is tested on SAP-C02
These questions test the same concept from different angles. Work through them to make sure you can recognise it however the exam phrases it.
Variation 1. A company is running a batch processing job on an EC2 instance that processes data from an S3 bucket and writes results to another S3 bucket. The job runs once per hour and takes about 20 minutes. The company wants to optimize costs by only paying for compute time when the job is running. Which solution is MOST cost-effective?
medium- A.Convert the batch job into an AWS Lambda function.
- B.Purchase a Reserved Instance for the EC2 instance to reduce hourly cost.
- C.Use a t3.micro instance and keep it running 24/7 since it's low cost.
- ✓ D.Use AWS Batch with spot instances to run the job only when needed.
Why D: AWS Batch automatically provisions and terminates EC2 instances based on job queue requirements, and it can use Spot Instances for significant cost savings. Option A (AWS Lambda) is wrong because the batch job takes 20 minutes, exceeding the 15-minute maximum execution time for Lambda functions. Option B (Reserved Instance) is wrong because it requires a 1-year commitment and still incurs costs for idle hours when the job is not running. Option C (t3.micro running 24/7) is wrong because while it is low-cost, it still charges for idle time, making it less cost-effective than only paying for compute during job execution.
JA
Written and reviewed by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
Last reviewed September 2026 · checked against the official Amazon Web Services exam blueprint
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