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    Elastic Compute Service:Set an automatic snapshot policy for a disk

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    Elastic Compute Service:Set an automatic snapshot policy for a disk

    Last Updated:Aug 26, 2025

    You can associate an automatic snapshot policy with a disk. After the policy is associated, Alibaba Cloud periodically creates automatic snapshots to back up disk data at the times specified in the policy.

    Precautions

    Before you set an automatic snapshot policy for a disk, note the following:

    • The snapshot service supports a quota of 1,000 automatic snapshots for each disk. If the number of automatic snapshots for a disk reaches this quota, the system deletes the earliest automatic snapshot created by the policy when a new snapshot is created.

    • If a disk has a large amount of data and the time required to create a snapshot exceeds the interval between two scheduled snapshot creation times, the following constraints apply:

      • ESSD series disks (ESSDs, ESSD AutoPL disks, ESSD Entry disks, and zone-redundant ESSDs)

        Snapshots can be created concurrently. For example, if you set the automatic snapshot creation times to 9:00, 10:00, and 11:00, and the snapshot creation task at 9:00 takes 70 minutes to complete (finishing at 10:10), the system still starts a new automatic snapshot task at 10:00 as scheduled.

        Up to 10 snapshots can be created concurrently. If the number of snapshots to be created at a specific time exceeds this limit, the task for that time is skipped.

      • Previous generation disks (standard SSDs, ultra disks, and basic disks)

        The next scheduled snapshot creation task is skipped. For example, if you set the automatic snapshot creation times to 9:00, 10:00, and 11:00, and the snapshot creation task at 9:00 takes 70 minutes to complete (finishing at 10:10), the 10:00 task is skipped. The next snapshot is created at 11:00.

    • The following constraints apply to the creation of automatic and manual snapshots:

      • If a snapshot is being manually or automatically created for a cloud disk when the point in time specified in the associated automatic snapshot policy is reached, the automatic snapshot cannot be created based on the policy at the point in time. An automatic snapshot is created for the disk at the next point in time specified in the automatic snapshot policy.

      • If an automatic snapshot is being created for a cloud disk, you cannot create a manual snapshot for the disk. Wait until the automatic snapshot is created.

    • A single disk does not support concurrent cross-region replication of snapshots to the same destination region. If a cross-region replication task is in progress for a disk when an automatic snapshot policy is executed, the policy's scheduled replication task for that time is skipped.

    • After an automatic snapshot is created, you are charged for snapshot storage in each region based on the snapshot size. For more information, see Snapshot billing.

    • After a snapshot is created, it is automatically stored in an Object Storage Service (OSS) bucket by default. You cannot select the OSS bucket for snapshot storage or view the snapshot data. For more information, see Snapshot storage location.

    • By default, a single disk can be associated with only one policy. To associate multiple policies, see Set multiple automatic snapshot policies for a single disk.

    Limits

    • Ensure that the disk is in the In Use or Unattached state.

      • If the disk is In Use, the associated instance must be in the Running or Stopped state. If the ECS instance is being stopped or restarted, the system does not execute the automatic snapshot policy.

      • If the disk is Unattached, it must have been previously attached to an ECS instance. You cannot set an automatic snapshot policy for a disk that has never been attached to an ECS instance.

        Note

        Because the disk has never been attached to an ECS instance, its data has not changed, and no snapshot is needed.

    • Each disk can be associated with only one automatic snapshot policy, but a single policy can be associated with multiple disks.

    Procedure

    Set an automatic snapshot policy for an existing disk

    • Method 1: Associate disks on the Automatic Snapshot Policies page

      You can associate an automatic snapshot policy with one or more disks on the Automatic Snapshot Policies page.

      1. Go to the ECS console - Automatic Snapshot Policies page.

      2. In the top navigation bar, select the region and resource group of the resource that you want to manage. 地域

      3. On the Automatic Snapshot Policies tab, find the policy you want to manage and click Associate Disks in the Actions column.

      4. In the Associate Disks dialog box, associate disks with the automatic snapshot policy.

        1. In the Available Disks section, select one or more disks and click the image icon.

        2. Click Associate.

      Note

      Later, you can also select one or more disks in the Selected Disks section and click the image icon to disassociate them from the automatic snapshot policy as needed.

    • Method 2: Set an automatic snapshot policy on the Disks page

      You can also set an automatic snapshot policy for a single disk on the Disks page.

      1. Go to ECS console - Block Storage.

      2. In the top navigation bar, select the region and resource group of the resource that you want to manage. 地域

      3. On the Disks page, find the disk you want to manage and click Set Snapshot Policy in the Actions column.

      4. In the Set Automatic Snapshot Policy dialog box, set an automatic snapshot policy for the disk.

        A snapshot policy has been created and associated with the disk

        If a snapshot policy has been created in the current region and is already associated with the disk, you can change the associated policy.

        1. From the Set Automatic Snapshot Policy drop-down list, select a new snapshot policy for the disk or select Create Automatic Snapshot Policy.

        2. Click Confirm To Enable Automatic Snapshot Policy.

        Note

        Later, you can also disassociate the snapshot policy from the disk as needed:

        1. Turn off the image switch.

        2. Click Confirm To Disable Automatic Snapshot Policy.

        A snapshot policy has been created but is not associated with the disk

        If a snapshot policy has been created in the current region but is not associated with the target disk, you can associate the policy with the disk.

        1. From the Set Automatic Snapshot Policy drop-down list, select an existing snapshot policy.

        2. Click Confirm To Enable Automatic Snapshot Policy.

        No snapshot policy has been created

        If no snapshot policy has been created in the current region, you can create one for the disk as needed.

        1. Set the automatic snapshot policy to Daily Backup, Weekly Backup, or Custom Policy.

        2. Configure the policy details based on the selected backup cycle. From the Specific Policy drop-down list, select Create Automatic Snapshot Policy or the system default policy (default_policy).

        3. Click Confirm To Enable Automatic Snapshot Policy.

    Set an automatic snapshot policy when you create an ECS instance

    When you create an ECS instance, you can also set an automatic snapshot policy for the system disk or data disks.

    1. Go to ECS console - Instance.

    2. In the top navigation bar, select the region and resource group of the resource that you want to manage. 地域

    3. On the Instances page, click Create Instance.

      • In the Storage section, for the Snapshot Service parameter, select an existing automatic snapshot policy for the system disk or data disks.

        Note

        If no snapshot policy has been created in the current region, you can select the system default policy (default_policy) or click Create Automatic Snapshot Policy on the right to go to the Snapshots page and create a policy. For more information, see Create an automatic snapshot policy.

      • For information about other parameter settings and the detailed procedure, see Create an instance using the custom launch template.

      image

    Related operations

    View created automatic snapshots

    When a scheduled time in the automatic snapshot policy is reached, a new snapshot is automatically created and listed on the Disk Snapshots page. The snapshot name starts with auto2.0, and its source is identified as Automatic Creation. Snapshots created by an automatic snapshot policy have a standard naming format: auto2.0_yyyyMMdd_SnapshotPolicyId, where:

    • auto2.0: Indicates an automatic snapshot, distinguishing it from a manual snapshot.

    • yyyyMMdd: The date the snapshot was created, where yyyy is the year, MM is the month, and dd is the day.

    • SnapshotPolicyId: The ID of the corresponding automatic snapshot policy.

    For example, auto2.0_20241225_sp-2zeff8vy17u91rn5**** indicates an automatic snapshot created on December 25, 2024, by the automatic snapshot policy sp-2zeff8vy17u91rn5****.image

    Note

    For information about the differences between automatic and manual snapshots, see Snapshot FAQ.

    Set automatic snapshots to be released with the disk

    By default, the lifecycle of an automatic snapshot is determined by the retention period of the automatic snapshot policy and is not affected when the disk is released. You can enable the Release With Disk property for automatic snapshots if needed.

    Important

    After you enable the Release With Disk property, when the disk is released (manually released, released with the instance, or when the system disk is replaced), the automatic snapshots are deleted along with the disk, even if their retention period has not expired.

    1. In the disk list, find the disk you want to configure. In the Actions column, choose 更多 > Edit Properties or click Edit Properties.

    2. In the Edit Disk Properties dialog box, select the Release With Disk option.

      Note

      Later, you can clear the Release With Disk option to disable this feature as needed.

    3. Click OK.