Create a snapshot for a cloud disk to back up disk data

Updated at: 2025-01-20 08:48

Before you perform operations, such as rolling back cloud disks, modifying critical system files, and replacing operating systems, we recommend that you create snapshots for system disks or data disks to back up data. If issues or data loss occurs, you can use the snapshots to restore data and ensure service continuity. This topic describes how to create a snapshot for a cloud disk.

Prerequisites

  • Elastic Compute Service (ECS) Snapshot is activated. For more information, see Activate ECS Snapshot.

  • The cloud disk for which you want to create a snapshot is in the In Use or Unattached state. Take note of the following items:

    • If the disk is in the In Use state, make sure that the ECS instance to which the disk is attached is in the Running or Stopped state.

    • If the disk is in the Unattached state, make sure that the disk was attached to an ECS instance at least once. Snapshots cannot be created for disks that were not attached to an ECS instance at least once.

Considerations

When you create a snapshot for a cloud disk, take note of the following items:

  • Do not perform operations that change the status of the associated ECS instance, such as stopping or restarting the instance. Otherwise, snapshot creation fails.

  • We recommend that you create snapshots during off-peak hours because snapshot creation degrades disk I/O performance by up to 10% and slows down data reads and writes.

  • If operations are performed on the disk and incremental data is generated while a snapshot is being created, the incremental data is not included in the snapshot.

  • You cannot resize the cloud disk when a snapshot is being created for the disk. Wait until the snapshot is created before you resize the cloud disk.

  • After you create snapshots, you are charged snapshot storage fees per region based on the total size of the snapshots stored in the region. For more information, see Snapshots.

  • When you use a cloud disk to create a dynamic extended volume or a RAID array, we recommend that you create a snapshot-consistent group and enable the application-consistent snapshot feature to ensure a consistent write order and crash consistency of data. For more information, see Create a snapshot-consistent group and Create application-consistent snapshots.

Procedure

This section describes how to create a snapshot for a cloud disk on the Snapshots page in the ECS console. You can also create a snapshot for a cloud disk on the Block Storage page.

  1. Go to the Snapshots page.

    1. Log on to the ECS console.

    2. In the left-side navigation pane, choose Storage & Snapshots > Snapshots.

    3. In the top navigation bar, select the region and resource group to which the resource belongs. 地域

  2. On the Disk Snapshots tab, click Create Disk Snapshot.

  3. In the Create Snapshot dialog box, configure the parameters. The following table describes the parameters.

    Parameter

    Description

    Parameter

    Description

    Resource Type

    Valid values: Instance and Cloud Disk. Default value: Cloud Disk. If you set the Resource Type parameter to Cloud Disk, select a cloud disk for which you want to create a snapshot.

    Note

    If you set the Resource Type parameter to Instance, select one or more ECS instances for which you want to create a snapshot-consistent group. Then, select the cloud disks for which you want to create snapshots from the ECS instances to ensure data consistency for the disks. For more information, see Create a snapshot-consistent group.

    Disk

    The cloud disk for which you want to create a snapshot. You can select a system disk or a data disk.

    Snapshot Name

    The name of the snapshot.

    Retention Period

    The number of days for which you want to retain the snapshot. Valid values: Permanently (Until Deleted) and Retained for.

    • Permanently (Until Deleted): The snapshot does not expire. After the maximum number of snapshots is reached, new snapshots cannot be created. To prevent unnecessary snapshot costs, you can delete snapshots based on your business requirements. For information about how to delete a snapshot, see Delete a snapshot.

    • Retained for: After the retention period of the snapshot ends, the snapshot expires and is automatically deleted.

    Note

    If the remaining retention period of a snapshot is a few days, such as three days, Released After {days} Days appears in the Retention Period column corresponding to the snapshot on the Disk Snapshots tab. You can extend the retention period of a snapshot before the snapshot expires. For more information, see Extend the retention period of a snapshot.

    Advanced Settings

    Instant Access

    By default, the instant access feature is enabled for Enterprise SSD (ESSD) series disks (ESSDs, ESSD AutoPL disks, ESSD Entry disks, and Regional ESSDs). Cloud disks of other categories do not support this parameter. For more information, see Use the instant access feature.

    Tag

    The tag key-value pairs that you want to add to the snapshot to facilitate management.

    Resource Group

    The resource group to which you want to assign the snapshot. You can use resource groups to manage snapshots at different levels.

  4. Click OK.

  5. (Optional) View the creation progress of the snapshot on the Disk Snapshots tab.

    image.png

    After you create the snapshot, the snapshot is automatically stored in an Object Storage Service (OSS) bucket. For more information, see Overview.

    • View the upload progress of the snapshot to OSS in the Progress column. When you move your pointer over Progress of Upload to OSS: xx%, the estimated remaining amount of time required to upload the snapshot is displayed.

      Note

      The estimated remaining amount of time required to upload a snapshot to OSS dynamically varies in real time based on multiple factors, including the size of the snapshot and the number and size of snapshots that are being created by other users.

      • A longer period of time is required to upload a larger snapshot to OSS.

      • The first snapshot of a cloud disk is a full snapshot. An extended period of time is required to create the first snapshot. Subsequent snapshots are incremental snapshots and do not require the same amount of time to be created as the first snapshot. The amount of time required to create an incremental snapshot varies based on the amount of data changed since the previous snapshot.

      • The peak periods of creating automatic snapshots are the early morning hours. The number and size of uploaded snapshots increase during peak periods, and the bandwidth that is allocated to each snapshot may decrease. The initial estimated amount of time required to upload each snapshot may increase. The number of snapshots that are being uploaded decreases over time. In this case, more bandwidth can be allocated to each snapshot, the transfer speed increases, and the estimated remaining amount of time required to upload each snapshot is reduced. To accelerate uploads, we recommend that you do not create manual snapshots during the peak periods.

    • If Progress of Upload to OSS: 100% is displayed, the snapshot is uploaded to OSS.

  • On this page (1, M)
  • Prerequisites
  • Considerations
  • Procedure
  • References
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