This section compares the features and applicable scenarios of OBS and file systems, helping you select the service appropriately.

• Features and Application Scenarios

  The file system has the following features:

  1. Standard file protocol: You can mount file systems to servers, the same as using the local directory.
  2. Data sharing: The same file system can be mounted to multiple servers, so that access to data can be shared.
  3. Private network: Data access must be performed in the internal network of the data center.
  4. The capacity of a single file system is high (at PB level) and the performance is excellent (at ms level), mainly for media editing, HPC, and file sharing scenarios.

  OBS has the following features:

  1. Provides the standard REST API. You need to use programming or third-party tools to access object storage.
  2. Data sharing: servers, embedded devices, IoT devices can use the same path to access shared object data in OBS.
  3. Public/private networks: Allows data to be accessed from public networks to meet Internet application requirements.
  4. Unlimited capacity and high performance (10 ms): Most suited for Web/Mobile, backup/archiving, and big data/IoT scenarios.

• API Function Comparison

  The following table compares a bucket in OBS with a directory in the file system. OBS does not have the hierarchical directory structure.

  Table 1 Comparison of the API between OBS and the file system

  OBS	File System
  Get Service	Obtain the directory list.
  Get Bucket	Obtain the file list.
  Put Object	Write data to a file.
  Append Object	Append data to a file.
  Get Object	Read a file.
  Delete Object	Delete a file.
  Not supported	Modify the file contents.
  Copy Object (copy the same name object in the same bucket), Put ACL	Modify properties of a file.
  Copy Object	Copy a file.

• Precautions for Mapping File Systems to OBS

  Many tools can map buckets to file systems. An object name can be mapped to a multi-level directory. For example, the object name test/ refers to a directory, and the object name test/test1.jpg refers to a file in the directory.

  Function simulation (such as renaming a directory) is resource consuming. Therefore, avoid performing such operations in a simulated file system. Try to simply write new files, delete files, read and write files.