Object Storage Showdown: S3 vs OSS vs COS

Object storage is the cornerstone of modern cloud architecture, powering everything from static asset hosting to data lake analytics. AWS S3, Alibaba Cloud OSS, and Tencent Cloud COS are the three most representative object storage services globally and in China. This article provides a comprehensive multi-dimensional comparison.

Basic Specifications

| Specification | AWS S3 | Alibaba Cloud OSS | Tencent Cloud COS | |--------------|--------|-------------------|-------------------| | Max Object Size | 5TB | 48.8TB | 48.8TB | | Objects per Bucket | Unlimited | Unlimited | Unlimited | | Min Storage Duration | None (Standard) | 30 days (IA/Archive) | 30 days (IA/Archive) | | Durability | 99.999999999% (11 nines) | 99.9999999999% (12 nines) | 99.9999999999% (12 nines) | | Availability | 99.99% (Standard) | 99.995% (Standard) | 99.99% (Standard) | | API Style | S3 API (industry standard) | S3-compatible | S3-compatible |

All three deliver exceptional durability and availability. Alibaba Cloud and Tencent Cloud claim 12 nines of durability—one more nine than AWS S3—but the practical reliability difference is negligible.

Storage Tiers

| Storage Tier | AWS S3 | Alibaba Cloud OSS | Tencent Cloud COS | |-------------|--------|-------------------|-------------------| | Hot Storage | Standard | Standard | Standard | | Infrequent Access | Standard-IA | Infrequent Access | Infrequent Access | | Archive | Glacier | Archive | Archive | | Deep Archive | Glacier Deep Archive | Cold Archive | Deep Archive | | Intelligent Tiering | S3 Intelligent-Tiering | OSS Intelligent Tiering | COS Intelligent Tiering | | Cold Storage | N/A | N/A | Cold Storage |

AWS S3 Intelligent-Tiering was the first automated tiering solution and supports 8 access tiers (including asynchronous monitoring tiers), offering the highest automation granularity. Alibaba Cloud OSS supports 4 tiers and Tencent Cloud COS offers similar functionality. All three implement automatic tiering based on access frequency, but AWS provides the finest granularity.

Performance Comparison

| Performance Dimension | AWS S3 | Alibaba Cloud OSS | Tencent Cloud COS | |----------------------|--------|-------------------|-------------------| | Upload Bandwidth | Multipart parallel upload | Multipart parallel upload | Multipart parallel upload | | First-Byte Latency | ~10-30ms | ~10-20ms | ~10-25ms | | Archive Retrieval | Minutes to hours | Minutes (accelerated) | Minutes | | Request Rate | 5500 GET/s per prefix | 3000 GET/s | 3000 GET/s | | Multi-Region Acceleration | CloudFront + S3 Transfer Acceleration | OSS Global Acceleration + CDN | COS Global Acceleration + CDN |

Alibaba Cloud OSS excels in first-byte latency within mainland China, and its accelerated archive retrieval can complete in minutes. AWS S3 leads in per-prefix request rates, suited for high-frequency access scenarios. Tencent Cloud COS has unique optimizations for audio/video file processing.

Security and Compliance

| Security Dimension | AWS S3 | Alibaba Cloud OSS | Tencent Cloud COS | |-------------------|--------|-------------------|-------------------| | Server-Side Encryption | SSE-S3, SSE-KMS, SSE-C | SSE-KMS, SSE-C | SSE-COS, SSE-KMS | | Client-Side Encryption | SDK support | SDK support | SDK support | | Versioning | Supported | Supported | Supported | | WORM | Object Lock (compliance mode) | Compliance retention policy | Compliance retention | | Access Logs | Server Access Logging | Access logging | Access logging | | VPC Endpoints | PrivateLink supported | VPC Endpoint supported | Intranet access supported | | WAF Integration | CloudFront + WAF | WAF supported | WAF supported |

AWS S3 Object Lock is the industry's most mature WORM solution, satisfying financial compliance requirements like SEC 17a-4. Alibaba Cloud and Tencent Cloud offer similar compliance retention features, but AWS has broader international compliance certifications.

Data Processing Capabilities

| Processing Dimension | AWS S3 | Alibaba Cloud OSS | Tencent Cloud COS | |---------------------|--------|-------------------|-------------------| | Image Processing | None (requires Lambda@Edge) | IMG image processing | Data Infinity image processing | | Video Transcoding | None (requires MediaConvert) | Video transcoding (MTS) | Cloud transcoding | | Content Moderation | None (requires Rekognition) | Content Security | Data Infinity moderation | | Metadata Extraction | None | Customizable | Customizable | | Event Notifications | S3 Event Notifications | OSS event notifications | COS event notifications | | Batch Operations | S3 Batch Operations | OSS batch processing | COS batch processing |

Alibaba Cloud OSS and Tencent Cloud COS include built-in image processing, video transcoding, and content moderation—no Lambda functions needed for common media processing tasks. AWS S3 favors decoupled architecture with independent PaaS services, which is more modular but more complex to configure.

Data Lake Integration

| Data Lake Dimension | AWS S3 | Alibaba Cloud OSS | Tencent Cloud COS | |--------------------|--------|-------------------|-------------------| | Data Catalog | Glue Data Catalog | DataLake Analytics | Data Lake Compute | | Query Engine | Athena | DataLake Analytics | Data Lake Compute | | ETL Orchestration | Glue ETL | DataWorks | Data Workshop | | Table Format Support | Iceberg, Delta, Hudi | Iceberg, Delta | Iceberg, Delta | | Access Management | Lake Formation | DataLake access management | Data Lake permissions |

AWS leads significantly in data lake ecosystem maturity, with S3 + Glue + Athena as the de facto industry standard. Alibaba Cloud and Tencent Cloud are rapidly catching up, with growing support for open table formats like Iceberg and Delta Lake.

Pricing Comparison

Benchmark: 1TB Standard storage, 1M GET requests, 100K PUT requests per month

| Pricing Dimension | AWS S3 | Alibaba Cloud OSS | Tencent Cloud COS | |-------------------|--------|-------------------|-------------------| | Storage Monthly | ~$23 | ~$16 | ~$15 | | GET Requests | $0.0004/1K | ~$0.0014/1K | ~$0.0014/1K | | PUT Requests | $0.005/1K | ~$0.0014/1K | ~$0.0014/1K | | Data Egress | $0.09/GB | ~$0.07/GB | ~$0.07/GB | | Archive Retrieval | $0.02-0.10/GB | ~$0.001-0.005/GB | ~$0.003-0.008/GB |

Alibaba Cloud OSS and Tencent Cloud COS are notably cheaper than AWS S3 on storage and request pricing, consistent with Chinese cloud providers' general pricing strategy. However, AWS often offers more competitive international data transfer rates.

Get the Best Storage Pricing Through Duoyun Cloud

Whether you choose AWS S3, Alibaba Cloud OSS, or Tencent Cloud COS, Duoyun Cloud as an official partner of all three can provide exclusive discounts below list price. We also represent GCP Cloud Storage, offering one-stop comparison to find the most cost-effective storage solution—saving you up to 30%. Visit duoyun.io for your quote today.