What Are the Precautions for Detaching a Disk from an ECS?

Scenarios

A disk attached to an ECS can function as a system disk or data disk.

• Disks mounted on /dev/sda or /dev/vda function as system disks. Currently, system disks must be detached offline. In this case, you must stop the ECS before detaching a system disk.
• Disks mounted on other mount points functions as data disks. In addition to offline detachment, a data disk can also be detached online if the server OS supports online detachment. In this case, you do not need to stop the running ECS.

This FAQ describes how to detach a disk from a running ECS.

Constraints

• The disk to be detached must be mounted on a mount point other than /dev/sda or /dev/vda.

  Disks mounted on /dev/sda or /dev/vda are system disks and cannot be detached from running ECSs.

• Before detaching a disk from a running Windows ECS, make sure that VMTtools have been installed on the ECS and that the tools are running properly.
• Before detaching a disk from a running Windows ECS, ensure that no program is reading data from or writing data to the disk. Otherwise, data will be lost.
• SCSI disks cannot be detached from running Windows ECSs.

• Before detaching a disk from a running Linux ECS, you must log in to the ECS and run the umount command to cancel the association between the disk and the file system. In addition, ensure that no program is reading data from or writing data to the disk. Otherwise, the disk will fail to be detached.

OSs Supporting Disk Detachment from a Running ECS

Online detachment is not supported by the ECSs running OSs not listed in the preceding table. For such ECSs, stop the ECSs before detaching disks from them to prevent any possible problems from occurring.