Use a snapshot-consistent group to simultaneously create snapshot backups for multiple disks - Elastic Compute Service

You can use a snapshot-consistent group to simultaneously create snapshots for multiple disks that are attached to one or more ECS instances in the same zone. This ensures time series consistency and crash consistency for data written across multiple disks. This topic describes how to create a snapshot-consistent group.

Notes

Before you create a snapshot-consistent group, note the following:

Precautions	Description
Impact on performance	During the first few seconds of snapshot creation, disk I/O may experience jitter (typically no more than 10%). Read and write performance returns to normal after the upload progress is displayed in the Progress column on the ECS Console - Snapshots page.
Billing	Creating a snapshot-consistent group is free of charge. However, you are charged storage fees for the snapshots based on their size and the duration for which they are stored. For more information, see Snapshot pricing.
Limits	The snapshot-consistent group feature supports only ESSD-series disks (ESSDs, ESSD AutoPL disks, and ESSD Entry disks) that do not have the multi-attach feature enabled. All disks in a snapshot-consistent group must reside in the same zone. You cannot specify a custom retention period for snapshots created in a snapshot-consistent group. By default, these snapshots are retained permanently. A snapshot-consistent group can span multiple ECS instances. However, a single group can contain up to 16 disks (including system and data disks), and the total disk capacity cannot exceed 32 TiB. Total concurrent quota: A maximum of 10 snapshot tasks—including manual snapshots, automatic snapshots, and snapshot-consistent groups—can run concurrently on a single disk. Snapshot-consistent group concurrency has the following limits: China (Hohhot), Philippines (Manila), China (Ulanqab), China (Heyuan), China (Guangzhou), Indonesia (Jakarta), Thailand (Bangkok), China (Hong Kong), China (Qingdao), China (Zhangjiakou), China (Beijing), and China (Shenzhen): No limit on individual tasks. You can create multiple snapshot-consistent groups concurrently, subject only to the total concurrent quota of 10 tasks. Other regions: Only 1 in-progress snapshot-consistent group task is allowed per disk. If such a task already exists, you cannot select the disk when creating a new snapshot-consistent group—even if the total number of tasks is below the quota.

For more information about creating snapshots, see the Notes section in Create a snapshot.

Prerequisites

The snapshot feature is enabled. For more information, see Enable snapshots.
Your ECS instances are in the Running or Stopped state, and the disks are in the In Use state.

Procedure

Go to the ECS Console - Snapshot-consistent Groups page.
In the top navigation bar, select the region and resource group of the resource that you want to manage.
On the Snapshot-consistent Groups tab, click Create Snapshot-consistent Group.

In the Create Snapshot dialog box, set the parameters for the snapshot-consistent group.

Parameter		Description
Resource Type		By default, Instance is selected. Choose one or more disks from your instances to create a snapshot-consistent group and generate snapshots for all selected disks, ensuring data consistency across them. Note You can also set Resource Type to Disk to create a snapshot for a single disk. For more information, see Create a snapshot.
Select Instances		Select one or more ECS instances for which you want to create a snapshot-consistent group.
Select Cloud Disk		Select the disks from your instances for which you want to create a snapshot-consistent group. Note If your instances have other disk types attached, you can select only ESSD-series disks (ESSDs, ESSD AutoPL disks, and ESSD Entry disks).
Snapshot-consistent Group Name		Enter a name for the snapshot-consistent group.
(Optional) Advanced Configuration	Application-consistent Snapshot	Enable Application-consistent Snapshot: Disabled by default. Select this option to enable application-consistent snapshots. Note If you require stricter data consistency, enable application-consistent snapshots when creating a snapshot-consistent group. This ensures internal data consistency within your applications. For more information, see Create an application-consistent snapshot. Application-consistent snapshots have specific usage limits. For more information, see Limits.
	Description	Enter a description for the snapshot-consistent group to simplify future management.
	Tag	Set a key-value pair as the tag for the snapshot-consistent group. You can use tags to manage resources uniformly.

Click Confirm.
(Optional) You can view the new snapshot-consistent group in the list. You can also click the group ID to view the details of the snapshots in the group.

References

You can also use the following API operations:
- CreateSnapshotGroup: Creates a snapshot-consistent group.
- DescribeSnapshotGroups: Queries snapshot-consistent groups.
- ModifySnapshotGroup: Modifies a snapshot-consistent group.
After you create a snapshot-consistent group, you can perform the following operations:
- Use the snapshot-consistent group to roll back disks. For more information, see Roll back disks using a snapshot-consistent group.
- Use an individual snapshot from the group to perform the following operations:
To reduce storage fees, you can periodically delete snapshot-consistent groups and their snapshots that you no longer need. For more information, see Delete a snapshot-consistent group.