- Job frequency: once per hour
- Runtime: ~15 minutes
- Compute requirement: ~64 vCPU, 512 GiB memory
1. AWS Lambda Cost Analysis
Lambda pricing basics:
- You pay for memory allocated × execution time.
- Lambda CPU is proportional to memory allocation, but even at maximum memory (10,240 MB), CPU is far below a dedicated 64 vCPU machine.
- This means your job cannot run on one Lambda invocation — you’d need to split it into parallel tasks.
Example scenario:
- Suppose we split into 64 parallel Lambda functions (1 vCPU each).
- Each Lambda invocation: 15 minutes × 64 functions = heavy orchestration overhead.
- Lambda cost formula:
Price = number of requests × price per request + execution time × memory allocated × price per GB-second
Quick estimate:
- Memory: max 10 GiB per Lambda
- Execution: 15 min = 900 sec
- Price per GB-sec: ~$0.00001667
- Cost per invocation: 10 GiB × 900 sec × $0.00001667 ≈ $0.15
- 64 invocations/hour → $9.60/hour purely compute cost.
- Plus orchestration overhead (Step Functions or EventBridge) adds complexity and cost.
- Also, splitting the job adds operational complexity and risk.
2. AWS Batch on EC2 Cost Analysis
EC2 pricing basics:
- Choose instance type that matches CPU/memory needs.
- Example:
m5.24xlarge= 96 vCPU, 384 GiB RAM - Approximate On-Demand cost: ~$4.608/hour (varies by region).
- You only need instance for ~15 minutes/hour.
Cost for your job:
- Instance usage: (15/60) hours = 0.25 hours × $4.608 = ~$1.15/hour
- Batch schedules the instance only when needed (if using Spot or On-Demand with Batch), so cost is close to this estimate.
- Spot pricing can reduce cost further, possibly below $0.50/hour.
- Operational overhead is minimal — AWS Batch handles provisioning, job scheduling, and retries.
Comparison Table:
| Option | Cost Estimate | Operational Overhead | Complexity |
|---|---|---|---|
| AWS Lambda | ~$9.60/hour + orchestration cost | High (manual orchestration, splitting job) | High |
| AWS Batch on EC2 | ~$1.15/hour (On-Demand) | Low (automated orchestration) | Low |
✅ Conclusion:
AWS Batch is much cheaper for large CPU workloads and greatly reduces operational complexity. Lambda in this scenario would be significantly more expensive and much harder to manage.
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