Create a snapshot for a system disk or data disk to back up disk data - Elastic Compute Service

Before you perform important operations, such as rolling back disks, modifying critical system files, and replacing operating systems, we recommend that you create snapshots for system disks or data disks to back up data. When issues or data loss occurs, you can use the snapshots to restore data and ensure service continuity. This topic describes how to create a snapshot for a disk.

Prerequisites

Elastic Compute Service (ECS) Snapshot is activated. For more information, see Activate ECS Snapshot.
The disk for which you want to create a snapshot is in the In Use or Unattached state. Take note of the following items:
- If the disk is in the In Use state, make sure that the ECS instance to which the disk is attached is in the Running or Stopped state.
- If the disk is in the Unattached state, make sure that the disk was attached to an ECS instance at least once. Snapshots cannot be created for disks that have never been attached to an ECS instance.

Considerations

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

Do not perform operations that change the status of the associated ECS instance, such as stopping or restarting the instance. Otherwise, snapshot creation fails.
We recommend that you create snapshots during off-peak hours because snapshot creation degrades disk I/O performance by up to 10% and slows down data reads and writes.
If operations are performed on the disk and incremental data is generated when a snapshot is being created, the incremental data is not included in the snapshot.
You cannot resize a disk for which a snapshot is being created. Wait until the snapshot is created before you resize the disk.
After you create snapshots, you are charged snapshot storage fees per region based on the total size of the snapshots that are stored in the region. For more information, see Snapshots.
When you use a disk to create a dynamic extended volume or a RAID array, we recommend that you create a snapshot-consistent group and enable the application-consistent snapshot feature to back up data. When a business system involves multiple disks, you can create a snapshot-consistent group to ensure a consistent write order and the crash consistency of business system data. For more information, see Create a snapshot-consistent group and Create application-consistent snapshots.

Procedure

This section describes how to create a snapshot for a disk on the Snapshots page in the ECS console. You can also create a snapshot for a disk on the Block Storage (Disks) page.

Log on to the ECS console.
In the left-side navigation pane, choose Storage & Snapshots > Snapshots.
In the top navigation bar, select the region and resource group to which the resource belongs.
On the Disk Snapshots tab, click Create Disk Snapshot.

In the Create Disk Snapshot dialog box, configure parameters. The following table describes the parameters.

Parameter	Description
Disk	The disk for which you want to create a snapshot. You can select a system disk or a data disk.
Snapshot Name	The name of the snapshot.
Retention Period	The number of days for which the snapshot is retained. Valid values: Permanently (Until Deleted) and Retained for. After the retention period of the snapshot ends, the system automatically deletes the snapshot. Note If the snapshot is about to be released in three days, Released After {days} Days is displayed in the Retention Period column corresponding to the snapshot on the Disk Snapshots tab. If you specify a retention period for the snapshot, you can extend the retention period of the snapshot before the snapshot expires. For more information, see Extend the retention period of a snapshot.
Instant Access	By default, the instant access feature is enabled for snapshots that are created only for Enterprise SSD (ESSD) series disks including ESSD disks, ESSD AutoPL disks, ESSD Entry disks, and Regional ESSDs (invitational preview) disks. Other categories of disks do not support this parameter. For more information, see Use the instant access feature.
Tag	The tag that you want to add to the snapshot. You can use tags to classify snapshots to facilitate search and batch operations.
Resource Group	The resource group to which you want to assign the snapshot. You can use resource groups to manage snapshots at different levels.

Click OK.
(Optional) View the creation progress of the snapshot on the Disk Snapshots tab.
After you create the snapshot, the snapshot is stored in an Object Storage Service (OSS) bucket. For more information, see How snapshots work.
- View the upload progress of the snapshot to OSS in the Progress column. When you move your pointer over Progress of Upload to OSS: xx%, the estimated remaining amount of time required to upload the snapshot is displayed.
  Note
  The estimated remaining amount of time required to upload a snapshot to OSS dynamically varies in real time based on multiple factors, including the size of the snapshot and the number and size of snapshots that are being created by other users.
  A longer period of time is required to upload a larger snapshot to OSS.
  The peak periods of creating automatic snapshots are the early morning hours. The number and size of uploaded snapshots increase during peak periods, and the bandwidth that is allocated to each snapshot may decrease. The initial estimated amount of time required to upload each snapshot may increase. The number of snapshots that are being uploaded decreases over time. In this case, more bandwidth can be allocated to each snapshot, the transfer speed increases, and the estimated remaining amount of time required to upload each snapshot is reduced. To achieve higher upload speeds, we recommend that you do not create manual snapshots during the peak periods.
- If Progress of Upload to OSS: 100% is displayed, the snapshot is uploaded to OSS.