• Object Storage Service

  1. Help Center
  2. Object Storage Service
  3. API Reference (OBS)
  4. Operations on Objects
  5. Upload Part

Upload Part

After initiating a multipart upload, you can use this operation to upload parts for the multipart upload using its uploadId.

In a multipart upload for a specific object, parts of the object can be uploaded in any sequence and multiple parts can be uploaded concurrently.

Part sizes range from 5 MB to 5 GB. However, in a complete multipart operation, the size of the last uploaded part must range from 0 to 5 GB. In addition, the uploadId of each part must be in the range of 1 to 10000.

This operation makes server-side encryption available.

When the same multipart of the same object is uploaded concurrently, the server complies with the Last Write Win policy.

The time of Last Write is the creation time of the multipart metadata. To ensure data security, you must add a lock to the client to ensure the upload consistency of the same multipart. There is no need to add a lock when different parts of the same object are uploaded.