Help Center> Image Management Service> User Guide (Paris Regions) > Overview> Constraints
Updated on 2024-03-01 GMT+08:00
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Constraints

This section describes the constraints on using IMS.

Table 1 Constraints on creating a private image

Item

Constraint

Maximum number of private images that can be created in a region

50

If you need more, submit a service ticket to increase your quota. For details, see

Maximum number of concurrent tasks for creating private images

40

NOTE:

Currently, only one image can be created in each task.

Creating a system disk image from an ECS
  • The ECS must be in the Stopped or Running state.

Creating a full-ECS image from an ECS or a CSBS or CBR backup
  • The ECS must be in the Stopped or Running state.
  • A CSBS or CBR backup can be used to create only one full-ECS image at a time.
  • A full-ECS image cannot be exported, replicated, or shared.
Table 2 Constraints on importing a private image

Item

Constraint

Importing a system disk image from an external image file

For details about constraints on external image files, see Preparing an Image File or Preparing an Image File.

Importing a system disk image from an ISO file
  • Register the ISO file as an ISO image, use the ISO image to create a temporary ECS, install an OS and related drivers on the ECS, and use the ECS to create a system disk image.
  • The ISO image cannot be replicated, exported, or encrypted.

Importing a data disk image from an external image file

The data disk capacity can be 40–2048 GB, and it must also be at least as big as the data disk in the image file.

Image format

VMDK, VHD, QCOW2, RAW, VHDX, QED, VDI, QCOW, ZVHD2, and ZVHD

Image size

The image size cannot exceed 128 GB.

If the image size is between 128 GB and 1 TB, convert the image file into the RAW or ZVHD2 format and import the image through fast import.
Table 3 Constrains on sharing images

Item

Constraint

Maximum number of tenants an image can be shared with

System disk image or data disk image: 128

Full-ECS image: 10

Maximum number of shared images that a tenant can receive

No limit

Private image status

Normal

Image sharing

Encrypted images and full-ECS images created from a CSBS backup cannot be shared with others.

Region
  • There are constraints on the region when cloud servers are created from a shared image. For example, a shared image can be used to create cloud servers only in the same region.
Table 4 Constraints on replicating an image

Item

Constraint

Maximum size of an image

128 GB

Maximum number of concurrent replication tasks per tenant

5

Private image status

Normal

Replicating images within a region
  • Full-ECS images cannot be replicated within the same region.
  • Private images created using ISO files do not support in-region replication.
Table 5 Constraints on exporting an image

Item

Constraint

Maximum size of an exported image

1 TB

Images larger than 128 GB only support fast export.

Formats of exported image files

VMDK, VHD, QCOW2, ZVHD, and ZVHD2

Private image status

Normal

Exporting an image
  • Encrypted images cannot be exported through fast export.
  • An image can only be exported to a Standard bucket that is in the same region as the image.
  • The following private images cannot be exported:
    • Full-ECS images
    • ISO images
    • Private images created from a Windows, SUSE, Red Hat, Ubuntu, or Oracle Linux public image
  • The image size must be less than 1 TB. Images larger than 128 GB support only fast export.
Table 6 Constraints on other image operations

Operation

Item

Constraint

Encrypting an image

Creating an encrypted image from an encrypted ECS or an external image file
  • An encrypted image cannot be shared with other tenants.
  • The key used for encrypting an image cannot be changed.

Deleting images

Private image status

A published private image cannot be deleted.

Creating cloud servers from an image

Number of cloud servers that can be concurrently created using a system disk image

Recommended value: ≤ 100

Tagging an image

Maximum number of tags that can be added to a private image

10

Other Constraints

  • If an ECS is frozen due to overdue payment, it cannot be used to create a private image. You must renew the ECS before using it to create a private image.
  • A private image containing a 32-bit OS cannot be used to create an ECS with larger than 4 GB of memory because the total available address space for a 32-bit OS is 4 GB.
Parent topic: Overview