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Custom images FAQ

Last Updated: Apr 11, 2018

How can I view data disks?

You can run a df command to view the usage of a data disk and the location where a file system is mounted, for example, df –lh.

You can run a fdisk command to query the partition information of data disks, for example, fdisk -l.

How can I detach a disk and delete data in the disk table?

If /dev/hda5 is mounted on /mnt/hda5, you can run any of the following commands to detach the mounted file system:

  • umount /dev/hda5
  • umount /mnt/hda5
  • umount /dev/hda5 /mnt/hda5

/etc/fstab is an important configuration file on Linux. It contains details of the file system and storage devices mounted at startup.

If you do not want to mount a specified partition when starting an instance, you must delete the corresponding statement lines from this file. For example, you can delete the following statement to detach xvdb1 at startup.

  • /dev/xvdb1 /leejd ext4 defaults 0 0

How do I know whether a data disk is detached and whether a custom image can be created?

  • Make sure that the statement line for automatically mounting the partition of the data disk has been deleted from /etc/fstab.

  • Run a mount command to view information about all mounted devices, and make sure that the execution results do not contain the information about the data disk partition.

After an instance is released, do its custom images still exist?


After an instance is released, do its snapshots still exist?

The manual snapshots are retained, while the automatic snapshots are cleared when an instance is released. For more information, see Automatic snapshot FAQs.

When the instance used to create a custom image expires or the data is released, are the custom images created from these images affected? Are the instances activated from these images affected?

Neither of them is affected.

Can I change the operating system of instances activated using a custom image? If I change the operating system, can the custom image still be used?

Yes. After the operating system is changed, the custom image can still be used.

Can I change the operating system of a system disk using a custom image?


Note: After the image on the system disk is replaced with a custom image, all data on the system disk is overwritten.

Can I replace the data on the system disk of another instance by using a created custom image?

Yes. However, you must note that the custom image overwrites all data on the system disk of the instance. For more information, see Create an instance by using a custom image.

Can I upgrade the CPU, memory, bandwidth, and hard disk of instances activated using a custom image?


Can a custom image be used across different regions?

No. Custom images can only be used within one region. For example, a custom image created for instances in the US West 1 region cannot be used to activate instances in the Asia Pacific SE 1 region.

However, to use a custom image across different regions, you can copy the image. For more information, see Copy an image.

Can I create a Pay-As-You-Go instance by using the custom image of a Subscription instance?