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FAQ about automatic snapshots

Last Updated: Mar 06, 2018

1. Is there any information I need to know about automatic snapshot policies?

  • You can customize automatic snapshot policies:
    • Automatic snapshots can be created for both system disks and data disks.
    • Snapshots can be created at 24 time points (on the hour) per day and repeated 7 days per week.
    • You can choose to retain snapshots for a period of time (1 ~ 65536 days) or permanently.
    • You can query the number of disks associated with an automatic snapshot policy and view its related details.
  • The name format of the automatic snapshots is: auto2.0_yyyyMMdd_1, for example, auto2.0_20140418_1.
  • You can manage automatic snapshots, including delete a snapshot, create a custom image using a snapshot, and create a disk with a snapshot.
  • The snapshot quota has been raised to 64 per disk.

2. Does a custom snapshot conflict with an automatic one?

Snapshots that are manually created do not conflict with auto snapshots. However, if you are performing an auto snapshot on a disk, you must wait for it to finish before manually creating a snapshot.

3. Can I retain automatic snapshots and prevent it from being automatically deleted?

You can choose to retain them permanently. However, when the snapshot quota for a disk, that is 64, has been reached, the system automatically deletes the oldest automatic snapshot to save a new one.

4. If an automatic snapshot is used to create a custom image or a disk, will this cause a failure in executing the automatic snapshot policy?


5. Does the system take an automatic snapshot if I do not configure any settings?

Snapshot 2.0 provides more options to define an automatic snapshot policy. The system takes an automatic snapshot of a disk only if you apply an automatic snapshot policy to the disk.

6. Can I delete automatic snapshots?

You can manually delete automatic snapshots. When the quota for a disk, that is 64, has been reached, the system automatically deletes the oldest automatic snapshot to save a new one.

7. Where can I find the exact time when an automatic snapshot was created?

You can see the exact creation time of each snapshot in the snapshot list on the ECS console.

8. How do I differentiate automatic snapshots from custom ones?

You can differentiate them by name: an automatic snapshot is named with this format, auto2.0_yyyyMMdd_1, for example auto2.0_20140418_1.

9. Will automatic snapshots be deleted if I change the system disk, my ECS instance expires, or I manually release the disks?

On the ECS console, choose Disks in the left pane and click More > Modify Attributes for the expected disk. If Delete automatic snapshots when releasing disk is selected (default setting), the automatic snapshots of the disk will be automatically deleted when the disk is released manually, when its instance is deleted, or when the system disk is changed. Deselect this option if you want to retain the snapshots.

10. Will the stored automatic snapshots be retained forever after the data disk or system disk is changed?

The automatic snapshot policy defines the period for retaining the automatic snapshots. They are automatically deleted when expiring.

11. Are custom snapshots deleted when an ECS instance expires or the disk is manually released?

No. Snapshots that are taken manually are retained until they are manually deleted.

12. Can I specify the disks for which an automatic snapshot is created?

Yes. You can apply an automatic policy to one or more disks. For more information, see Apply automatic snapshot policies to disks.

13. Does ECS provide automatic backup function?

ECS provides automatic and custom snapshot functions, allowing you easily back up and roll back snapshot data.

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