Manage snapshots-Simple Application Server(SAS)-阿里云帮助中心

A snapshot is a point-in-time backup of a disk. You can use snapshots for tasks like daily data backups, disaster recovery, and custom image creation. This topic describes how to create and delete snapshots, roll back a disk from a snapshot, and create a custom image from a snapshot in the Simple Application Server console.

Limitations

Note

Snapshot creation for Simple Application Server is free.

You can create a maximum of three snapshots for each Simple Application Server instance.
The total number of snapshots for your Alibaba Cloud account is limited to three times the number of your Simple Application Server instances, up to a maximum of 15.
Releasing an instance upon expiration also deletes its associated snapshots.
Snapshots created before an instance reset or image replacement are retained. However, you cannot use these snapshots to roll back a disk.

Billing

Creating snapshots is free of charge.

Create a snapshot

Go to the Servers page in the Simple Application Server console.
Find the target instance and click its instance ID on the card.
Click the Disks tab.
In the Actions column for the system disk or data disk, click Create Snapshot.

If your instance does not have a data disk, you can only create a snapshot for the system disk.
In the Create Snapshot dialog box, confirm the disk information, specify a name for the snapshot, and then click OK.

To ensure the snapshot is created successfully, do not stop or restart the instance during the process, which typically takes 10 to 30 minutes.
Click the Snapshots tab to view information about the created snapshot.

Roll back a disk from a snapshot

Limitations

Note that snapshots created before an instance reset or image replacement cannot be used for disk rollbacks.

Important considerations

Rolling back a disk is an irreversible action. Any data written to the disk between the snapshot creation time and the rollback time will be permanently lost. To prevent accidental data loss, back up the latest data by creating a new snapshot before you roll back the disk.
If the instance is in the Running state when you start the rollback, the system automatically stops the instance before rolling back the disk.

Procedure

Go to the Servers page in the Simple Application Server console.
Find the target instance and click its instance ID on the card.
Click the Snapshots tab.
Find the target snapshot and in the Actions column, click Roll Back.
In the Roll Back Disk dialog box, confirm the information and click OK.
In the Roll-back Tip dialog box, confirm the information again and click OK.

If the instance is in the Running state, the system stops the instance before starting the rollback process.
When the rollback completes, click Start to restart the instance.

Delete a snapshot

Warning

Deleting a snapshot is irreversible. Before you proceed, ensure the snapshot data is no longer needed.

Go to the Servers page in the Simple Application Server console.
Find the target instance and click its instance ID on the card.
Click the Snapshots tab.
Find the target snapshot and in the Actions column, click Delete.

Frequently asked questions

Q1: Snapshot policies

A1: No, you must create snapshots manually. For specific snapshot quantity limits, see the Limitations section.

Q2: Snapshot rollback after reset

A2: You cannot directly use a pre-reset snapshot for rollback. However, the following workaround is available:

Use the snapshot that was created before the instance was reset to create a custom image. For more information, see Create a custom image.
Reset the instance using the custom image that you created. For more information, see Reset a server.

Warning
If the instance contains important data, resetting it will cause data loss. We recommend that you create a snapshot to back up your data before you reset the instance. For more information, see Create a snapshot.

Related operations

You can also use a snapshot to create a custom image to save an instance's data. You can then share the image with ECS or use it to create other Simple Application Server instances with the same configurations. For more information, see Overview of custom images.