Restrictions

This section describes the restrictions on using OBS features.

**Table 1** Use restrictions
Restriction Item	Description
Bandwidth	By default, the maximum bandwidth for read/write (GET/PUT) requests of a single account is 16 Gbit/s. If the actual bandwidth reaches the threshold, flow control will be triggered.
Queries per second (QPS)	Default maximum QPS allowed by a single account: 6,000 write requests (PUT Object) per second 10,000 read requests (GET Object) per second 1,000 listing requests (LIST) per second NOTE: If you use sequential prefixes (such as timestamps or alphabetical order) for object naming, object access requests may be concentrated in a specific partition, resulting in access hotspots. This limits the request rate in a hotspot partition and increases access delay. Random prefixes are recommended for naming objects so that requests are evenly distributed across partitions, achieving horizontal expansion.
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 hosting access domain name. For example, you have a bucket named test-bucket in the my-kualalumpur-1 region, and you want to access the ACL of an object named test-object in the bucket. The correct URL is https://test-bucket.obs.my-kualalumpur-1.alphaedge.tmone.com.my/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 leverage the fine-grained permission control capability 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, neither the entire OBS system nor any single bucket has limits on storage capacity or the number of objects that 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.
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 using the batch upload mode, the maximum size of the file is 5 GB. If you use OBS Browser+ or an API, you can upload a single object of up to 48.8 TB. The batch upload function is available only when the following conditions are met: The bucket version must be 3.0. If versioning is disabled and the name of a newly uploaded file is the same as that of a file in the bucket, the newly uploaded file automatically overwrites the existing file and does not retain the ACL information of the existing file. If the name of the newly uploaded folder is the same as that of a folder in the bucket, the two folders will be merged, and files in the new folder will overwrite the same-name files in the old folder. If versioning is enabled and the name of a newly uploaded file is the same as that of a file in the bucket, a new version is added to the existing file. 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.
Bucket policy	There is no limit on the number of bucket policies (statements) for a bucket. However, the total size of JSON descriptions of all bucket policies in a bucket cannot exceed 20 KB.
ACL	A bucket ACL supports a maximum of 100 permission grants. An object ACL supports a maximum of 100 permission grants.
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.
Restoring objects from Cold storage	If a Cold object is being restored, you cannot suspend or delete the restore task. You cannot re-restore an object that is in the Restoring state. After an object is restored, an object copy in Standard storage class will be generated. This way, there is an object in Cold storage class and also a copy in Standard storage class in the bucket. The Standard object copy will be automatically deleted upon its expiration.
Deleting objects	If versioning is not enabled for a bucket, deleted objects cannot be recovered. Exercise caution when performing this operation.
Parallel File System	See the Parallel File System Feature Guide.
User-defined domain name binding	Only buckets whose version is 3.0 support user-defined domain name binding. Currently, user domain names bound to OBS only allow access requests over 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 and lowercase letters.