On OBS, buckets are containers that store objects. OBS provides flat storage methods based on buckets and objects. All objects in a bucket are at the same logical layer, eliminating the traditional multi-layer directory structure of file systems.

OBS has the following storage classes: Standard, Infrequent Access, and Archive. In such a manner, OBS meets customers' requirements on storage performance and costs. When creating a bucket, you can set a storage class for the bucket. On OBS, each object has a storage class that is the same as its owning bucket.

On OBS, each bucket name must be globally unique and cannot be changed. When a bucket is created, its access control list (ACL) is generated by default. The ACL records authorized users' permissions such as the read and write permissions. Only authorized users can perform bucket operations, such as creating, deleting, viewing, and setting ACLs for buckets. A user can create a maximum of 100 buckets. However, the number and total size of objects in a bucket are not restricted. Users do not need to worry about system scalability.

As OBS is based on RESTful HTTP and HTTPS, you can use URLs to locate resources.

Figure 1 illustrates the relationship between objects and buckets.

Figure 1 Relationship between objects and buckets