Object chunking allows the client to notify the origin server to return partial content within a specified range. It helps accelerate delivery of large files. This feature also helps reduce the consumption of back-to-origin traffic and improve resource response speed. This topic describes how to enable object chunking and related precautions.

Background information

When you configure object chunking, take note of the following points:
  • Ensure that the origin server supports range requests. If the HTTP request header contains the range field, the origin server must be able to return 206 Partial Content.
  • Object chunking is optional and is disabled by default.

Procedure

  1. Log on to the Alibaba Cloud CDN console.
  2. In the left-side navigation pane, click Domain Names.
  3. On the Domain Names page, find the target domain name and click Manage.
  4. In the left-side navigation pane of the specified domain, click Video.
  5. In the Object Chunking section, click Modify.

    Object chunking
  6. Object Chunking can be set to On, Off, or Force.
    Object chunking Description Example
    On Requests with the Range parameter can be sent to the origin server. The origin server returns a file that has the number of bytes within the range specified by the Range parameter. CDN nodes return the file to the client. When a request sent from the client to a CDN node contains range: 0-100, the request received by the origin server also contains range: 0-100. The origin server returns a file with 101 bytes in the range of 0 to 100 to the CDN node. Then, the CDN node returns this file to the client.
    Off A CDN node redirects a request for the entire file on the origin server. The client automatically disconnects the HTTP connection to the CDN node after receiving a file that has the number of bytes within the range specified by the Range parameter. The requested file is not cached on the CDN node. This results in a low cache hit rate and large back-to-origin traffic. When a request sent from the client to a CDN node contains range: 0-100, the request received by the origin server does not contain the Range parameter. The origin server returns a complete file to the CDN node. However, the CDN node returns a file with the first 101 bytes to the client. Because the HTTP connection is disconnected, this file is not cached on the CDN node.
    Force The requests with the range parameter are forcibly sent to the origin server. When you set Object Chunking to Force, make sure that the origin server supports the Range parameter.
    Note

    When you set Object Chunking to Force, all chunked requests are forcibly sent to the origin server.

  7. Click OK.