Updated on 2026-08-21 GMT+08:00

Configuring WORM for Objects

If you want to prevent any user (including the bucket or object owner) from modifying or deleting specific objects in an OBS bucket for a specified period, you can configure object-level WORM.

This section describes how to configure WORM for objects when uploading them or after they are uploaded.

Constraints

A bucket-level WORM policy applies only to objects uploaded after the policy is configured. To protect existing objects, configure object-level WORM separately.
The metadata of a WORM-protected object can still be modified.

Important Notes

Before configuring object-level WORM, you must enable bucket-level WORM. If an object is protected by both bucket-level and object-level WORM, the object-level WORM policy takes precedence.
The retention period of object-level WORM can only be extended but cannot be shortened.
If you have deregistered your account or your account has been frozen, the WORM-protected objects will be permanently deleted.
WORM does not protect parts generated during multipart uploads.
If a bucket has WORM enabled, an append upload on this bucket will fail, with a 403 error returned.
Only the compliance mode is supported.

Access Control

To configure an object-level WORM policy, you must be the object owner or have the required permission. For authorization details, see Configuring WORM Retention for an Object.

Prerequisites

WORM has been enabled for the bucket.

Configuring WORM When Uploading Objects

You can use OBS Console or APIs to configure object-level WORM.

Using OBS Console

In the navigation pane of OBS Console, choose Buckets.
In the bucket list of OBS Console, click the desired bucket to go to the Objects page.
On the object list page, click Upload Object.

You can also go to the folder that the file is to be uploaded to and click Upload Object.

Batch upload is used as an example here. For regions that support only single upload, perform operations as prompted.

If the files that you want to upload to OBS are stored in Microsoft OneDrive, it is recommended that the names of these files contain a maximum of 32 characters to ensure compatibility.

Figure 1 Uploading objects

Under Configure Advanced Settings (Optional), specify the WORM retention.

For other parameters about uploading objects, see Using OBS Console.

Click to enlarge

**Table 1** Object-level WORM parameters
Parameter	Description
Retention	Specify the retention policy for objects. You can choose to inherit the bucket's retention policy or configure a separate one. Inherit from bucket: The objects inherit the bucket's default retention policy. If the bucket has no default retention, the objects are not protected by WORM. Configure: Configure a separate retention policy for objects. This policy protects only the objects you upload in this operation from being deleted or overwritten. It takes precedence over the bucket's default retention policy.
Extend To	Specify a date when Retention is set to Configure. Before this date, OBS prevents protected object versions from being deleted.

Click OK.

Using APIs

Configuring WORM Retention for an Object

Configuring WORM or Extending the Retention Period After Objects Are Uploaded

You can use OBS Console or APIs to configure object-level WORM.

If an object does not have WORM configured or its retention period needs to be extended, perform the following steps:

Using OBS Console

In the navigation pane of OBS Console, choose Buckets.
In the bucket list of OBS Console, click the desired bucket to go to the Objects page.
In the object list, locate the object for which you want to configure WORM or extend the retention period, choose More > Extend Retention Period, and select a date.

Figure 2 Extending the retention period

A retention period can be extended, but cannot be shortened.

Assume an object version is protected until March 30, 2023. If you extend the retention period on March 1, 2023, you can set it to March 31, 2023 or any later date. If you extend the retention period on April 1, 2023, you can set it to the current day (April 1, 2023) or any later date. If the current day is used, the object version is no longer protected by WORM after 24:00 on that day.
Click OK.