If your business requires different snapshot creation times, frequencies, and retention periods for the same disk, you can attach multiple automatic snapshot policies to it. This meets diverse backup needs, such as frequent short-term backups and long-term data retention.
Feature changes
Before feature change | After feature change |
You can attach only one automatic snapshot policy to a single disk. | You can attach up to 10 automatic snapshot policies to each disk. |
If an automatic snapshot policy is already attached to the target disk, applying a new policy replaces the existing one. | If an automatic snapshot policy is already attached to the target disk, applying a new policy adds it without replacing existing policies. Important Detach automatic snapshot policies you no longer need to avoid unexpected charges. |
Applicability
Ensure the disk meets one of the following conditions:
The disk is attached to an ECS instance in the Running or Stopped state.
The cloud disk is Available and was previously mounted to an ECS instance.
Call DescribeDisks and check the AttachedTime field to determine if the disk has attachment history.
Procedure
Configure automatic snapshot policies for a single disk
Go to ECS console - Block Storage. In the top navigation bar, select the target region and resource group.
In the Actions column of the target disk, click Configure Snapshot Policy.
On the Configure Automatic Snapshot Policy page, add or delete policies. A single disk supports up to 10 automatic snapshot policies.
Add a policy: From the Automatic Snapshot Policy drop-down list, select an existing policy or click Create Policy. Follow the on-screen instructions to complete the creation, and then click Confirm Settings.
Delete a policy: In the Automatic Snapshot Policy list, click the X icon next to the policy, then click Confirm Settings.
ImportantAfter deleting an automatic snapshot policy, snapshots are no longer automatically created based on that policy. Ensure your data is protected.
Attach disks to an automatic snapshot policy
Go to ECS console > Automatic Snapshot Policies. In the upper-left corner of the page, select the resource group and region where the target resource resides.
In the Actions column of the target policy, perform the required operation.
Attach disks: Click Attach Disk. In the Available Disks section, select the target disk, then click Confirm Attach.
You cannot select disks already attached to this policy or disks that have reached the limit of 10 attached policies.
Detach disks: Click Detach Disk. In the Available Disks section, select the target disk, then click Confirm Detach.
ImportantAfter detaching a disk, snapshots are no longer automatically created for it based on this policy. Ensure your data is protected.
Billing details
Creating a snapshot policy is free. However, after successful execution, charges apply based on task type. You can reduce snapshot storage costs by enabling automatic snapshots to be released with their disks, periodically deleting unused automatic snapshots, and archiving snapshots.
Automatic snapshot creation tasks: All snapshots created by a policy incur standard snapshot storage fees based on snapshot size.
Cross-region replication tasks: If cross-region replication is enabled for a policy, you incur snapshot replication traffic fees and standard snapshot storage fees in the destination region, in addition to standard snapshot fees in the source region.
Quotas and Limits
Each disk supports up to 10 attached automatic snapshot policies.
A single disk has a limit on concurrent snapshot creation tasks (including both automatic and manual). If this limit is exceeded when a policy triggers, the task is skipped and retried at the next scheduled time. Task limits vary by disk type:
Disk type
Task limit
ESSD series disks (ESSD, ESSD AutoPL, ESSD Entry, and zone-redundant ESSD)
10
Previous-generation disks (standard SSD, ultra disk, basic disk)
1
If a policy enables cross-region snapshot replication, ensure no other replication task exists for the same disk, source region, and destination region. If one exists, the new task is skipped and retried at the next scheduled time.
For the maximum number of automatic snapshots per disk, see Snapshot limits. When the automatic snapshot count reaches this limit, the system deletes the oldest automatic snapshot created by the policy. Plan your snapshot retention period carefully to avoid accidental deletion of important snapshots.
More operations
Enable automatic snapshots to be released with their disks
By default, automatic snapshots follow the retention period defined in their policy and are not released when the disk is released. Enable the Delete Automatic Snapshots While Releasing Disk property as needed.
After enabling Delete Automatic Snapshots While Releasing Disk, when you release the disk (manually, with its instance, or by replacing the operating system), automatic snapshots are deleted immediately—even if their retention period has not expired.
Go to ECS console - Block Storage. In the top navigation bar, select the target region and resource group.
In the Actions column of the target disk, click .
In the Modify Disk Attributes dialog box, select the Delete Automatic Snapshots While Releasing Disk option.
You can clear this option later to disable Delete Automatic Snapshots While Releasing Disk
Click OK.
How do I view created automatic snapshots?
After policy execution, snapshots appear automatically on the ECS console > Snapshots page.
Automatic snapshots use the naming format auto2.0_yyyyMMdd_SnapshotPolicyId. The Source is Automatic Creation. The components are:
auto2.0: Indicates an automatic snapshot.
See Snapshot FAQ for differences between automatic and manual snapshots.
yyyyMMdd: Snapshot creation date, where yyyy is year, MM is month, and dd is day.
SnapshotPolicyId: ID of the automatic snapshot policy used to create the snapshot.
For example, auto2.0_20241225_sp-2zeff8vy17u91rn5**** indicates an automatic snapshot created on December 25, 2024, with policy ID sp-2zeff8vy17u91rn5****.