If multiple data disks are attached to the ECS used to create a private image, ECSs created from the image may be unavailable. Therefore, you need to detach all data disks from the ECS before using it to create a private image.
This section describes how to detach all data disks from an ECS.
You have logged in to the ECS used to create a Linux private image.
Run the following command to check the number of disks attached to the ECS:
fdisk -l
mount
/dev/vda1 on / type ext4 (rw,relatime,data=ordered)
/dev/vda1 on / type ext4 (rw,relatime,data=ordered)/dev/vdb1 on /mnt/test type ext4 (rw,relatime,data=ordered)
vi /etc/fstab
The /etc/fstab file contains information about the file systems and storage devices automatically attached to the ECS when the ECS starts. The configuration about data disks automatically attached to the ECS needs to be deleted, for example, the last line shown in the following figure.
Figure 1 EVS disk configuration in the fstab file

Run the following command to detach the disks:
umount /dev/vdb1
mount
If the command output contains no information about the data disks, they have been detached from the ECS.