AWS Certified Solutions Architect – Associate (SAA-C03)Design Cost-Optimized ArchitecturesMedium
A data analytics company processes large datasets daily using Amazon EMR clusters. The input data is stored in Amazon S3, and the processed output is also written back to S3. The company wants to optimize the data transfer costs associated with moving data between S3 and EMR. What is the most cost-effective architectural consideration?
- AUse AWS Storage Gateway to cache S3 data locally for EMR.
- BCompress data before transferring it to and from S3.
- CUse S3 Transfer Acceleration for all data transfers.
- DEnsure S3 buckets and EMR clusters are in the same AWS Region.
Show answer & explanationAnswer & explanation
Correct answer: D. Ensure S3 buckets and EMR clusters are in the same AWS Region.
Data transfer between S3 and EMR within the same AWS Region is free. Cross-region data transfer incurs charges. Therefore, ensuring both services are in the same region is the most fundamental and cost-effective way to minimize data transfer costs in this scenario.
Why the other options are wrong
- A. AWS Storage Gateway is for hybrid cloud storage and is not typically used to optimize data transfer costs between S3 and EMR within AWS; it would add complexity and potentially cost.
- B. Compressing data reduces the volume of data transferred, which helps, but it doesn't eliminate the per-gigabyte cost of cross-region transfer and adds compute overhead for compression/decompression. It's a good practice but not the primary cost-saving mechanism compared to same-region placement.
- C. S3 Transfer Acceleration speeds up cross-region transfers but incurs additional costs and doesn't eliminate transfer charges, making it less cost-effective than same-region placement.
AWS Same-Region Data Transfer Cost
Data transfer between AWS services within the same AWS Region is generally free of charge, or significantly cheaper than cross-region or internet data transfer.
- Inter-AZ data transfer within the same region is charged.
- Data transfer between services (e.g., S3 to EC2) within the same region is often free.
- Cross-region data transfer incurs charges.
- Design for same-region placement to minimize costs.
Memory trick: Keep your data 'home' in the same region to avoid travel fees.