• Object Storage Service

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  6. Restoring a Cold File on OBS

Restoring a Cold File on OBS

You need to restore a Cold object before downloading it.


The Cold storage class is applicable to archiving rarely-accessed (such as once a year) data. The application scenarios include data archiving and long-term data retention for backup. OBS Cold is secure, durable, and inexpensive, which can replace tape libraries. However, it can take up to hours to restore data from OBS Cold.

If a Cold object is being restored, you cannot suspend or delete the restoration task.

You cannot restore an object that is in the Restoring state.


  1. Log in to OBS Browser.
  2. Click the bucket in which the file that you want to restore resides.

    The object list is displayed.

  3. Click next to the file that you want to restore. Alternatively, you can select an object and click on the top of the object list.

    Before restoring objects, you need to configure the validity period and restoration speed of the objects. Table 1 describes the parameters.

    Table 1 Parameters for restoring objects




    Name of the object to be restored.

    Storage Class

    Storage class of the object to be restored.


    The file size of the object to be restored.

    Validity Period

    Time duration when an object remains in the Restored state after being restored. The timing starts as the object restoration is completed. The value is an integer ranging from 1 to 30 (days). The default value is 30.

    For example, you set Validity Period to 20 when restoring an object. After 20 days starting from the time when the object is successfully restored, the object's status will change from Restored to Unrestored.


    Restoration speed of an object.

    • Expedited: Allows you to restore the cold objects within 1 to 5 minutes.
    • Standard: Allows you to restore your cold objects within 3 to 5 hours.
    • Bulk: Bulk retrievals are the lowest-cost retrieval option of OBS, enabling you to retrieve large amounts, even petabytes, of data in a day at a low cost. Bulk retrievals typically complete within 5 to 12 hours.

  4. Click OK to confirm the restoration of Cold files.

    Click and the Properties dialog box is displayed, as shown in Figure 1. You can view the restoration status.

    Figure 1 Properties of the restored object

    You can download the file only after its status changes to Restored. You can click in the upper right corner to refresh the restoration tasks and to view the restoration progress. The system also automatically refreshes the restoration tasks every 5 minutes.


    The system checks the file restoration status once per day at 00:00 (GMT±00:00). The expiration time is counted starting from the time when the last check was complete.

Follow-up Procedure

Within the validity period of an object, you can repeatedly restore the object. The validity period of the object is counted starting from the time when the latest restoration is completed. By doing so, you can prolong the validity period of an object.


If an object is to be restored for a second time, the expiration time set for the second restoration must be later than that set for the first restoration.