How to Choose Between CFS, BOS and CDS
Updated at：2025-11-11
This document outlines the differences between Cloud File System (CFS), Baidu AI Cloud Object Storage (BOS), and Cloud Disk Server (CDS) to help you select the most suitable Baidu AI Cloud storage service. The main distinctions are highlighted in the table below.
| Comparison items | Cloud File System (CFS) | Baidu Object Storage (BOS) | Cloud Disk Server (CDS) |
|---|---|---|---|
| Features | CFS uses a hierarchical directory structure for storage. Data is saved as files and accessed through directories and file paths, similar to traditional local file systems. It supports POSIX-standard operations (e.g., read/write permission management) and provides features like data sharing, high throughput, high IOPS, and efficient random file read/write capabilities. | BOS employs a flat structure where data is stored as independent objects. Each object has a unique ID and supports customizable metadata. This structure ensures high scalability and flexibility for object storage. BOS supports public network access and is ideal for low-cost storage and sharing of massive datasets. It works well for data with high read frequency, low write frequency, and minimal post-writing modifications (e.g., images, videos, backup files). | CDS is a type of block storage similar to a physical hard drive. It supports partitioning, formatting, and file system creation. CDS delivers high performance, low latency, and efficient random read/write capabilities. Its data is stored in multiple replicas within the same availability zone to mitigate single-point failures and supports elastic management such as online capacity expansion and disk type modification. |
| Application scenarios | Content management & web applications, big data analytics, pan-entertainment streaming media processing, and enterprise office file sharing. For details, see CFS Application Scenarios. | Global data distribution, cold data archiving, data disaster recovery & backup, high-performance big data computing, and multimedia data processing. For details, see BOS Application Scenarios. | Cloud service storage, critical application data storage, and consistent replication in complex environments. For details, see CDS Application Scenarios. |
| Access mode | Cloud resources (e.g., BCC cloud servers, GPU cloud servers, CCE containers) can access and modify data using POSIX APIs. | Users can perform concurrent file reading and appending through SDKs, APIs, and peripheral tools. | CDS is a "bare disk," requiring partitioning, file system creation (e.g., ext4 for Linux, NTFS for Windows), and mounting to a BCC instance for normal data operations like read/write. |
| Minimum latency | Millisecond-level. For details, see CFS Product Specifications. | Tens of milliseconds. For details, see BOS Usage Limits. | Microsecond-level. For details, see Disk Performance. |
| Maximum throughput | 40 GB/s. For details, see CFS Product Specifications. | Public network bandwidth limit: 10 Gbit/s (about 1 GB/s); Intranet bandwidth limit: 50 Gbit/s (about 6 GB/s). For details, see BOS Usage Restrictions. | Several GB/s. For details, see Disk Performance. |
| Maximum IOPS/QPS | Maximum IOPS: 300K. For details, see CFS Product Specifications. | Upload QPS per bucket: 1,500 q/s; Download QPS: Unrestricted. Upload QPS for a single hot object: 200 q/s; Download QPS for a single hot object: 1,000 q/s . For details, see BOS Usage Limits. |
Maximum IOPS: 100K. For details, see Disk Performance. |
| Capacity | <100PB | Uncapped | GB~TB |
| Protocol/API | NFS, SMB | HTTP/HTTPS | Virtual block device protocol API |