Constraints

Access rules

In consideration of the DNS resolution performance and reliability, OBS requires that the bucket name must precede the domain when a request carrying a bucket name is constructed to form a three-level domain name, also mentioned as virtual-hosted-style access domain name.

For example, you have a bucket named test-bucket in the eu-de region, and you want to access the ACL of the test-object object in the bucket. The correct access URL is https://test-bucket.obs.eu-de.otc.t-systems.com/test-object?acl.

Buckets

• On OBS, each bucket name must be unique and cannot be changed.
• After you create a bucket, its name and region cannot be changed.
• An account (including all IAM users under this account) can create a maximum of 100 buckets and parallel file systems. You can use the fine-grained access control of OBS to properly plan and use buckets. For example, you can create folders in a bucket for storing objects with different prefixes and use fine-grained permission control to implement permission isolation between departments.
• By default, there is no limit on the storage capacity of the entire OBS system or a single bucket, and any number of objects can be stored.
• A bucket can be deleted only after all objects in the bucket have been deleted.
• The name of a deleted bucket can be reused for another bucket or a parallel file system at least 30 minutes after the deletion.

Bucket inventories

See Bucket Inventory Overview.

Uploading objects

• OBS Console supports uploading files in a batch. A maximum of 100 files can be uploaded in a batch with the total size of no more than 5 GB. If you upload only one file in a batch upload, it cannot exceed 5 GB in size.
• If you use OBS Browser+ or an API, you can upload a single object of up to 48.8 TB.
• Batch upload is available only when:

  The bucket version is 3.0.

• If versioning is disabled for your bucket and you upload a new file with the same name as the one you previously uploaded to your bucket, the new file automatically overwrites the previous one and does not retain its ACL information. If you upload a new folder using the same name that was used with a previous folder in the bucket, the two folders will be merged, and files in the new folder will overwrite those with the same name in the previous folder.
• After versioning is enabled for your bucket, if the new file you upload has the same name as the one you previously uploaded to the bucket, a new file version will be added in the bucket.
• Though any UTF-8 characters can be used in object keys (object names), it is recommended that object keys be named according to the object key naming guidelines. These guidelines help object key names substantially meet the requirements of DNS, web security characters, XML analyzers, and other APIs.

Deleting objects

If versioning is not enabled for a bucket, deleted objects cannot be recovered.

Restoring Cold objects

• If a Cold object is being restored, you cannot suspend or delete the restore task.
• You cannot restore an object in the Restoring state.
• After an object is restored, an object copy in the Standard storage class will be generated. This way, there is a Cold object and a Standard object copy in the bucket at the same time. The Standard object copy will be automatically deleted upon its expiration.

Lifecycle management

There is no limit on the number of lifecycle rules in a bucket, but the total size of XML descriptions about all lifecycle rules in a bucket cannot exceed 20 KB.

Cross-region replication

See Cross-Region Replication Overview.

User-defined domain name binding

• Only buckets whose version is 3.0 or later support the binding of user-defined domain names.
• By default, user-defined domain names allow requests for OBS over only HTTP.
• A user-defined domain name can be bound to only one bucket.
• Currently, the suffix of a user-defined domain name can contain 2 to 6 uppercase or lowercase letters.

ACLs

• A bucket ACL can have up to 100 grants. The total bucket ACL size cannot exceed 50 KB.
• An object ACL can have up to 100 grants. The total object ACL size cannot exceed 50 KB.

Bucket policies

There is no limit on the number of bucket policies (statements) for a bucket, but the JSON descriptions of all bucket policies in a bucket cannot exceed 20 KB in total.

Parallel file systems

See the Object Storage Service Parallel File System Feature Guide.