You can create snapshots for multiple disks together by creating a snapshot for the Elastic Compute Service (ECS) instance to which these disks are attached. When a business system spans multiple disks on an ECS instance, you can create a snapshot for the instance to ensure a consistent write order and crash consistency of business system data.

Scenarios

  • If a business system spans multiple disks (including the system disk and data disks) on an ECS instance, you can create snapshots for these disks together by creating a snapshot for the instance. This ensures that the write order of data to each volume remains consistent. Example scenarios to which instance snapshots are applicable:

    MySQL clusters are built on ECS instances, a single Logical Volume Manager (LVM) logical volume is created across multiple volumes, and Oracle or SAP High-performance Analytic Appliance (SAP HANA) clusters are migrated to the cloud.

  • When a business system spans multiple disks on an ECS instance, the same backup policy must be applied to the disks.

Precautions

The amount of time required to create a snapshot for the instance depends on the sizes of the selected disks for which to create snapshots. The first snapshot of each disk is a full snapshot and takes a long time to create. Subsequent snapshots of the disk are incremental snapshots. It does not take as long to create an incremental snapshot, and the amount of time required varies based on the amount of data changed since the previous snapshot. The more data that has changed, the longer it takes. If you want to immediately use a snapshot after it is created, you can enable the instant access feature. For more information, see Enable or disable the instant access feature.

When you create a snapshot for an instance, take note of the following items:

  • The instance must be in the Running or Stopped state.
  • The instance snapshot feature can be used to create snapshots only for enhanced SSDs (ESSDs) that are in the In Use state. If the instance has disks of other categories attached, these disks are skipped and only snapshots of ESSDs are created when you create an instance snapshot.
  • A single instance snapshot can contain snapshots of up to 10 disks including the system disk and data disks, and cannot exceed 32 TiB in size.
  • To ensure that services are not affected, we recommend that you create instance snapshots during off-peak hours.
  • Created snapshots are permanently stored unless you delete them. We recommend that you delete unnecessary snapshots on a regular basis to prevent extra fees incurred by snapshot storage.

Billing

Instance snapshots are billed based on their size. After the instant access feature is enabled for an instance snapshot, you are charged both the snapshot storage fee and the instant access feature fee. For more information, see Snapshots.

Procedure

  1. Log on to the ECS console.
  2. In the left-side navigation pane, choose Instances & Images > Instances.
  3. In the top navigation bar, select a region.
  4. Find the instance for which you want to create a snapshot and choose More > Disk and Image > Create Instance Snapshot in the Actions column.
  5. In the Create Instance Snapshot dialog box, configure the parameters in the following table to create an instance snapshot.
    Parameter Description
    Select cloud disk Select disks on the instance, for which to create snapshots.
    Snapshot parameter settings ECS instance snapshot name Enter a name for the instance snapshot to make the snapshot easy to identify.
    Description Enter a description for the instance snapshot to make the snapshot easy to identify.
    Snapshot speed available
    • Enable Instant Access: You can select this option to enable the instant access feature. By default, this feature is disabled.
      Note The instant access feature supports only ESSDs. For more information, see Enable or disable the instant access feature.
    • Snapshot Speed Available Duration: After you enable the instant access feature, you can specify a validity duration for the feature. The instant access feature is automatically disabled when the specified duration expires.
    Application-consistent snapshot Enable Application-consistent Snapshot: You can select this option to enable the application-consistent snapshot feature. By default, this feature is disabled.

    For more information about how to enable the application-consistent snapshot feature, see Create application-consistent snapshots in the ECS console.

    Note The application-consistent snapshot feature is now available in the China (Hong Kong), Singapore (Singapore), China (Hangzhou), China (Shanghai), and China (Beijing) regions.
  6. Click OK.
    After the instance snapshot is created, you can choose Storage & Snapshots > Snapshots in the left-side navigation pane and click the Instance Snapshots tab to view the snapshot.

You can use the created instance snapshot to roll back disks or create images. For more information, see Roll back a disk by using an instance snapshot or Create a custom image from a snapshot.