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Home/Questions/Cloud/Tools/How would you optimize cost when using AWS for large-scale data processing?

How would you optimize cost when using AWS for large-scale data processing?

Cloud/Toolsmedium0.7 min readPremium

**Architectural cost logic**: At scale, 10–20% savings = millions. Prioritize by spend: compute (Glue/EMR/Lambda), storage (S3), and data transfer. **Compute**: Right-size—Glue bills by DPU-minute (10 DPU minimum); profile jobs and start at 10, scale only if I/O-bound. Use Spot...

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Frequency
Low
Asked at 1 company
Category
179
questions in Cloud/Tools
Difficulty Split
104E|27M|48H
in this category
Total Bank
1,863
across 7 categories
Asked at these companies
Wipro
Key Concepts Tested
partition

Why This Question Matters

This medium-level Cloud/Tools question appears frequently in data engineering interviews at companies like Wipro. While less common, it tests deeper understanding that distinguishes strong candidates. Mastering the underlying concepts (partition) will help you answer variations of this question confidently.

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Break this problem into components. Identify the core trade-offs involved, then walk the interviewer through your reasoning step by step. Demonstrate awareness of edge cases and production considerations - this is what separates good answers from great ones.

Expert Answer
132 words

Architectural cost logic: At scale, 10–20% savings = millions. Prioritize by spend: compute (Glue/EMR/Lambda), storage (S3), and data transfer. Compute: Right-size—Glue bills by DPU-minute (10 DPU minimum); profile jobs and start at 10, scale only if I/O-bound. Use Spot for Glue/EMR where fault-tolerance exists (checkpoints, idempotent writes); we achieved 40% EMR savings. Reserved Instances/Savings Plans for steady-state (e.g., always-on clusters). Storage: S3 Intelligent-Tiering for unknown access patterns—no retrieval fees vs. Glacier. Compress data (Parquet/ORC)—3–5× reduction cuts scan costs in Athena. S3 lifecycle to Glacier for cold data; delete incomplete multipart uploads. Query cost: Athena charges $5/TB scanned—partitioning + columnar formats + partition projection can cut scans by 80%. Governance: Cost Explorer, Budgets, tags for chargeback. At 100 TB storage + 50 TB monthly scans, savings from compression and tiering can exceed $5K/month.

The complete answer continues with detailed implementation patterns, architectural trade-offs, and production-grade considerations covering performance optimization and real-world examples.

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