Amazon·Software Engineer·Onsite - System Design / Architecture·Senior

Senior

Jul 2026

Summary

Did a system design round for a solutions architect role at Amazon. Just one question but it required knowing the actual differences between storage types, not just buzzwords.

Questions Asked (1)

What is the difference between file storage, object storage, and blob storage?

System DesignTechnical Trade-offs

Author's notes

I knew the broad strokes but fumbled the blob vs object distinction because they're genuinely close.

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AI HintsAI Generated

Suggested Approach

Start by defining each storage type in terms of its data model and access method, then compare them across dimensions like scalability, performance, cost, and use cases. Emphasize that blob storage is a subtype of object storage, and highlight how each aligns with different application needs.

Pro tip: Relate the concepts to AWS services (e.g., EBS for file, S3 for object) and discuss trade-offs in real-world scenarios, showing you understand both theory and practical implementation.

1. Define File Storage

Explain that file storage organizes data in a hierarchical structure of files and folders, accessed via file-level protocols like NFS or SMB. It's ideal for shared file systems and applications requiring low-latency access.

2. Define Object Storage

Describe object storage as a flat namespace where data is stored as objects (data + metadata + unique ID) in buckets, accessed via HTTP APIs. It offers massive scalability and is suited for unstructured data.

3. Clarify Blob Storage

Clarify that blob storage is essentially object storage for binary large objects (blobs), often used interchangeably with object storage. Mention that 'blob' emphasizes the storage of large binary data like images or videos.

4. Compare Key Dimensions

Contrast the three across dimensions: data organization (hierarchical vs flat), access protocols (file-level vs HTTP/REST), scalability (limited vs virtually unlimited), performance (low latency vs high throughput), and cost.

5. Discuss Use Cases and Trade-offs

Provide examples: file storage for shared directories, object storage for backups and media, blob storage for large binary content. Discuss when to choose each based on consistency, durability, and access patterns.

Key Points to Mention

File storage uses a hierarchical structure and file-level protocols (NFS, SMB), while object storage uses a flat namespace and RESTful APIs.
Object storage is highly scalable and durable, often eventually consistent, whereas file storage provides strong consistency and low latency.
Blob storage is a type of object storage optimized for large binary objects, and the terms are often used interchangeably.
AWS examples: EBS/EFS for file storage, S3 for object storage (which also handles blobs).
Trade-offs: file storage for shared, low-latency access; object storage for cost-effective, massive scale, and unstructured data.
Consider access patterns: file storage for random reads/writes, object storage for whole-object operations.

AI-generated suggestions, not part of the candidate's original notes. May be inaccurate — verify before relying on them.