Automatic snapshot policy-Elastic Compute Service(ECS)-阿里云帮助中心

You can use an automatic snapshot policy to create automatic snapshots of your disks at scheduled times. This protects your disk data and reduces the risk of data loss that can occur if you forget to create manual snapshots.

Scenarios

You can use an automatic snapshot policy to create regular snapshots of your disks and retain them for a specified period. This provides regular backups to recover from data loss or system failures caused by issues such as accidental deletion or viruses, ensuring business continuity.

Function introduction

The following list describes the common operations for automatic snapshot policies, from creation to deletion.

Function	Description
Create automatic snapshot policy	Configure settings such as the schedule and retention period for automatic snapshots.
Apply automatic snapshot policy to a disk	Associate an existing automatic snapshot policy with a disk. The system then creates snapshots automatically at the scheduled times defined in the policy.
Modify automatic snapshot policy	Update settings such as the start time or retention period of an existing automatic snapshot policy.
Schedule automatic snapshot creation	The system creates snapshots automatically based on the schedule defined in the automatic snapshot policy.
Delete automatic snapshot policy	Delete an automatic snapshot policy when it is no longer needed.
Delete snapshots	You can delete automatic snapshots in the following ways: Manually delete an automatic snapshot. This does not affect the automatic snapshot policy that created it. If you enable the delete automatic snapshots when releasing disk property, automatic snapshots are deleted when the associated disk is released. Automatic snapshots are deleted automatically after they exceed their retention period defined in the policy. If the number of automatic snapshots exceeds your quota, the system deletes the oldest snapshots first.

Billing details

Creating an automatic snapshot policy is free of charge. However, you are charged for snapshot storage based on the size of the snapshots and their retention period. For more information, see Snapshot billing.

Limits

Note the following limits when you use automatic snapshot policies:

Limit	Description
Snapshot quota	Each account can retain up to 100 automatic snapshot policies per region. For the number of automatic snapshot policies and snapshots allowed per disk, see Snapshot limits. Note When the number of automatic snapshots for a disk reaches its quota, the oldest snapshots are automatically deleted.
Elastic Block Storage types	ESSD PL-X disks, local disks, and elastic ephemeral disks do not support snapshots.
Other limits	The following constraints apply during manual and automatic snapshot creation: ESSD series disks (ESSD, ESSD AutoPL, ESSD Entry, and ESSD zone-redundant disks) A single disk supports the concurrent creation of manual and automatic snapshots. However, the number of concurrent snapshots that can be created is limited. For more information, see Snapshot limits. If the number of concurrent snapshots that are being created for a disk reaches the upper limit, subsequent snapshot creation tasks fail. Previous generation disks (standard SSDs, ultra disks, and basic disks) Concurrent creation of manual and automatic snapshots is not supported. At the point in time when an automatic snapshot is scheduled to be created, if a snapshot (manual or automatic) is being created for the disk, the system does not create an automatic snapshot at this point in time. An automatic snapshot is created at the next scheduled point in time. If an automatic snapshot is being created for a disk, you must wait for the automatic snapshot to be created before you can manually create a snapshot.

Differences between automatic and manual snapshots

Both automatic and manual snapshots back up disk data at a specific point in time. They differ in their creation methods and naming conventions, as described in the following table:

Difference

Automatic snapshot

Manual snapshot

Creation method

Create snapshots using an automatic snapshot policy.

After creating and associating a policy with a disk, the system creates snapshots automatically based on the policy schedule.

You must create it manually each time.

You can customize snapshot parameters as needed when creating a snapshot.

Snapshot name

Snapshot names are generated automatically by the system.

Names start with auto2.0 and follow the format auto2.0_yyyyMMdd_SnapshotPolicyId, where:

auto2.0 indicates an automatic snapshot, distinguishing it from manual snapshots.
yyyyMMdd is the snapshot creation date (y = year, M = month, d = day).
SnapshotPolicyId is the ID of the automatic snapshot policy used.

You can customize settings when you create a snapshot.