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  6. Basic OBS Concepts

Basic OBS Concepts

This section describes concepts related to OBS, including the object, bucket, Access Key ID (AK), and Secret Access Key (SK).


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

For details about objects, see section 1.3.1 "Object" in the Object Storage Service User Guide.


A bucket is a virtual container used to store objects on OBS. OBS provides flat storage methods based on buckets and objects. All objects in a bucket are at the same logical layer, eliminating the multi-layer directory structure of file systems.

Figure 1 illustrates the relationship between objects and buckets.

Figure 1 Relationship between objects and buckets

For details about buckets, see section 1.3.2 "Bucket" in the Object Storage Service User Guide.

AK and SK

A user's account provided by OBS contains an AK and an SK. The AK and SK are used for user identity authentication.

After subscribing to OBS, you can log in to My Credential and create AKs and SKs based on site requirements. The system identifies users who access the system by AKs, and SKs are used for key authentication. For details about objects, see section 3.2.3 "Creating Access Keys (AKs and SKs)" in the Object Storage Service User Guide.

  • One AK maps to only one user but one user can have multiple AKs.
  • One SK maps to one AK, forming a key pair for accessing OBS and thereby ensuring access security.