If a Pay-As-You-Go cloud disk is attached to an ECS instance as a data disk, you can detach it from the instance and release it. However, if the disk is used as a system disk, you cannot detach it.

When detaching a cloud disk, consider the following:

  • Only the Pay-As-You-Go cloud disks in the In Use state and used as a Data Disk can be detached.
  • You cannot detach a local disk.
  • For a Windows instance:
    • To guarantee data integrity, we recommend that you stop writing or reading the files on the cloud disk. Otherwise, data may be lost.
    • Before detaching a cloud disk in the ECS console, you must connect to the instance and set its status to Offline in Disk Management.

  • For a Linux instance:

    • Before detaching a cloud disk in the ECS console, you must connect to the instance and run umount to unmount the partitions.
    • If you have configured the /etc/fstab file to automatically mount the partitions at the startup of the instance, before detaching it, you must delete the configurations from the /etc/fstab file. Otherwise, you cannot connect to the instance after the instance is restarted.

The following table describes the actions available for you to detach a cloud disk in the ECS console.

Scenario Action
You want to detach one or more cloud disks from one instance. Detach cloud disks on the Instance Disk page.
You want to detach one specific cloud disk. Detach a cloud disks on the Disk List page.

Detach cloud disks on the Instance Disk page

On the Instance Disks page, you can delete one or more cloud disks that are attached to the instance.

Prerequisites

The cloud disks are attached to the instance and its status is In Use.

If you are detaching a cloud disk from a Linux instance, and you have configured the /etc/fstab file to mount the partitions at the startup of the instance, you must first delete the configurations.

Procedure

To detach a cloud disk from the Instance Disks page, follow these steps:

  1. Connect to the instance and unmount its partitions. According to the operating system, follow the recommended steps detailed in the following table.
    Operating system Steps
    Linux Run umount [partition]. For example, umount /dev/vdb1.
    Windows Start Disk Management, right-click the disk name (for example, Disk 2) and then click Offline.
  2. Log on to the ECS console.
  3. In the left-side navigation pane, choose Instances & Images > Instances.
  4. Find the target instance and click its ID to go to the Instance Details page.
  5. In the left-side navigation pane, click Disks.
  6. Find the target cloud disk and then, in the Actions column, select More > Unmount.

    Only cloud disks that have the following attributes can be detached:

    • Status must be In Use.
    • Unmountable must be Yes.
    • Type must be Data Disk.
  7. In the dialog box, click Confirm.
  8. Optional. If you want to detach multiple cloud disks, repeat steps 7 and 8 as required.

When the status of the cloud disk becomes Unmounted, the disk is detached.

Detach a cloud disks on the Disks page

On the Disk List page, you can detach a specific cloud disk from an ECS instance.

Prerequisites

The cloud disk is attached to the instance and is in the In Use state.

If you are detaching a cloud disk from a Linux instance, and you have configured the /etc/fstab file to mount the partitions at the startup of the instance, delete the configurations.

Procedure

To detach a cloud disk on the Disk List page, follow these steps:

  1. Connect to the instance and unmount the partitions. According to the operating system, follow the recommended steps detailed in the following table.
    Operating system Steps
    Linux Run umount [partition]. For example, umount /dev/vdb1.
    Windows Start Disk Management, right-click the disk name (for example, Disk 2) and then click Offline.
  2. Log on to the ECS console.
  3. In the left-side navigation pane, choose Storage & Snapshots > Disks.
  4. Find the target cloud disk and then, in the Actions column, select More > Unmount.

    Only cloud disks that have the following attributes can be detached:

    • Status must be In Use.
    • Unmountable must be Yes.
    • Type must be Data Disk.
  5. In the dialog box, click Confirm.

When the status of the cloud disk becomes Unmounted, the disk is detached.

Related API

DetachDisk

What to do next

If you no longer need the disk, you can release it.