Detach a data disk

Step 1: Change the billing method of the data disk from subscription to pay-as-you-go

If your data disk uses the pay-as-you-go billing method, skip this step.

If your data disk uses the subscription billing method, the data disk cannot be detached, shown as in the following figure. You must change the billing method of your data disk to pay-as-you-go. For more information, see Change the billing method from subscription to pay-as-you-go.

Step 2: Detach the data disk from within the operating system of the instance to which the disk is attached

If the data disk is partitioned and has file systems mounted, perform the following operations to detach the data disk from within the operating system of the instance to which the disk is attached:

For a Linux instance, perform the following steps:

1. Connect to the Linux instance.
   For more information, see Connect to a Linux instance by using password authentication.
2. Run the following command to view the mount information of the data disk:

   df -h

   A command output similar to the following one is displayed. In this example, the /dev/vdb1 partition of the data disk is used. In actual scenarios, choose the data disk partitions whose mount information you want to view.
3. Run the umount command to unmount the file systems from the data disk partitions.
   For example, you can run the following command to unmount the file system from the /dev/vdb1 partition of the data disk:

   umount /dev/vdb1

4. Run the following command to view the UUID information of the data disk partitions:

   blkid

   The following command output shows the UUID information of the /dev/vdb1 partition of the data disk.
5. Run the following command to check whether the /etc/fstab file contains the automatic mount configuration information of the file systems in the data disk partitions:

   cat /etc/fstab

   Find the UUID information obtained in the previous step in the command output. The file system mounted to the /dev/vdb1 partition is configured in /etc/fstab, as shown in the following figure.
6. Delete the automatic mount configuration information of the file systems in the data disk partitions from /etc/fstab.
   Note If you do not delete the automatic mount configuration information of the file systems in the data disk partitions from /etc/fstab, the instance cannot be restarted after you detach the data disk from the instance in the ECS console.
   1. Run the following command to edit /etc/fstab:

      vim /etc/fstab

   2. Press the I key to enter the edit mode.
   3. Delete or comment out the automatic mount configuration information of the file systems in the data disk partitions.
      For example, you can add # before the line of the automatic mount configuration information to comment it out.
   4. Press the Esc key, enter :wq, and then press the Enter key to save your changes and exit the edit mode.

For a Windows instance, perform the following steps:

1. Connect to the Windows instance.

   For more information, see Connect to a Windows instance by using password authentication.

2. On the Windows Server desktop, click the Server Manager icon in the lower-left corner.
   
3. In the upper-right corner of the Server Manager window, choose Tools > Computer Management.
4. In the left-side navigation pane, choose Computer Management (Local) > Storage > Disk Management.
5. Right-click the disk that you want to detach and select Offline.
   

Step 3: Detach the data disk in the ECS console

You can detach the data disk on the Instances or Disks page. Perform the following operations to detach the data disk on the Instances page in the ECS console:

1. Log on to the ECS console.
2. In the left-side navigation pane, choose Instances & Images > Instances.
3. In the top navigation bar, select a region.
4. Find the instance from which you want to detach the data disk and click the instance ID.
5. On the Instance Details page, click the Cloud Disk tab.
6. Find the data disk that you want to detach and choose More > Detach in the Actions column.
   Note If No is displayed in the Detachable(All) column, the data disk cannot be detached. In this case, go to Step 1: Change the billing method of the data disk from subscription to pay-as-you-go.
7. In the Detach Disk dialog box, click OK.

You can also choose Storage & Snapshots > Disks to go to the Disks page to detach the data disk.