Help Center > Object Storage Service > FAQ > OBS Basics > What Is an Object?

What Is an Object?

An object is a basic data unit of OBS. It contains both data and metadata that describes data attributes. Data uploaded to OBS is stored into buckets as objects.

An object consists of a key, metadata, and data.
  • A key specifies the name of an object. An object key is a character string ranging from 1 to 1024 characters in UTF-8 format. The object key for each object in a bucket must be unique.
  • Metadata provides a description of objects. Metadata contains system metadata and user metadata. All metadata is uploaded to OBS as key-value pairs.
    • System metadata is automatically generated by OBS and is used for processing object data. System metadata includes Date, Content-length, Last-modify, and Content-MD5.
    • User metadata is specified when users upload objects and is used to describe objects.
  • Data is the information contained by an object.

Generally, objects are managed as files. However, as an object-based storage service, OBS does not involve files or folders. For easy data management, OBS provides a method to simulate folders. By adding a slash (/) in an object name, for example, test/123.jpg, you can simulate test as a folder and 123.jpg as the name of a file under the test folder. However, the key remains test/123.jpg.