A snapshot-consistent group captures snapshots of multiple cloud disks simultaneously, ensuring write-order consistency and crash consistency across all disks. Use it when your application spans multiple Elastic Block Storage (ESSD) cloud disks and you need a consistent point-in-time backup across all of them.
Prerequisites
Before you begin, make sure you have:
The snapshot service enabled. For more information, see Enable the snapshot service.
Target ECS instances in the Running or Stopped state
Target cloud disks in the In Use state
Limitations
Supported disk types: ESSD, ESSD AutoPL, ESSD Entry, and regional-redundant ESSD (only when the multi-attach feature is disabled). Regional-redundant ESSDs can only be grouped with other regional-redundant ESSDs.
Same zone required: All cloud disks in a group must be in the same zone.
No custom retention period: Snapshots in a group are retained until you manually delete them.
Disk count and capacity limits: Cloud disks in a group can come from different ECS instances, subject to the following limits:
In the following regions, a group can contain up to 128 cloud disks with a total capacity of up to 256 TiB: China (Hohhot), Thailand (Bangkok), South Korea (Seoul), Malaysia (Kuala Lumpur), UK (London), SAU (Riyadh - Partner Region), UAE (Dubai), Japan (Tokyo), Philippines (Manila), China (Guangzhou), China (Qingdao), US (Silicon Valley), China (Hong Kong), Singapore, China (Fuzhou - Local Region - Closing Down), China (Nanjing - Local Region - Closing Down), China (Wuhan - Local Region), Mexico, Indonesia (Jakarta), China (Shanghai) Finance, China (Shenzhen) Finance, China (Chengdu), US (Virginia), China (Ulanqab), China (Zhangjiakou), and China (Heyuan).
In all other regions, a group can contain up to 16 cloud disks with a total capacity of up to 32 TiB.
Concurrent snapshot quota: A single cloud disk supports a maximum of 10 concurrent snapshot tasks (manual, automatic, and snapshot-consistent group snapshots combined). Disks at this limit cannot be added to a new group.
Creating a snapshot-consistent group is free of charge. Storage fees apply based on snapshot size and retention period. For more information, see Snapshot billing.
For additional precautions that apply to all snapshot types, see Create a snapshot for a disk.
Create a snapshot-consistent group
Tip: Add a tag to the group before clicking OK. Tags let you filter, manage, and track costs across snapshot groups without opening each one individually.
In the top navigation bar, select the region and resource group of the ECS instances you want to back up.
On the Snapshot-consistent Groups tab, click Create Snapshot-consistent Group.
In the Create Snapshot dialog box, configure the following parameters.
Parameter Description Resource Types Select Instance (default) to pick disks from one or more instances, which ensures cross-disk consistency. To snapshot a single disk instead, select Disks — see Create a snapshot for a disk. Select Instances Select the ECS instances whose disks you want to include. Select Disks From the selected instances, choose the ESSD, ESSD AutoPL, ESSD Entry, or regional-redundant ESSD disks to include. Regional-redundant ESSDs can only be grouped with other regional-redundant ESSDs. Snapshot-consistent Group Name Enter a name for the group. (Optional) Advanced settings — Application-consistent snapshot Select Enable Application-consistent Snapshot to capture application-level consistency in addition to crash consistency. Disabled by default. For requirements and limitations, see Create an application-consistent snapshot and Limits of application-consistent snapshots. (Optional) Description Enter a description to help identify the group later. (Optional) Tag Add key-value tags to categorize and manage the group. Click OK.
(Optional) On the Snapshot-consistent Groups tab, locate the group in the list to confirm it was created. You can also click the group ID to view the individual snapshots within it.
During the first few seconds of snapshot creation, cloud disk I/O may jitter, which typically does not exceed 10%. After the upload progress appears in the Progress column on the Snapshots page, read and write performance returns to normal.
What's next
After creating a snapshot-consistent group, you can:
Roll back multiple disks at once using the group: Roll back disks by using a snapshot-consistent group
Perform the following operations on individual snapshots within the group:
Delete snapshot-consistent groups and their snapshots when no longer needed to reduce storage costs: Delete a snapshot-consistent group
API operations
You can also manage snapshot-consistent groups using the following API operations:
CreateSnapshotGroup — Create a snapshot-consistent group
DescribeSnapshotGroups — Query snapshot-consistent groups
ModifySnapshotGroup — Modify a snapshot-consistent group