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Updated on 2024-02-01 GMT+08:00
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What Are the Differences Between Images and Backups?

CBR and Image Management Service (IMS) have some complementary functions and can be used together in certain scenarios. Like CBR, IMS can also be used to back up ECSs.

Differences Between Backups and Images

Table 1 lists the differences between them.

Table 1 Differences between backups and images

Item

CBR

IMS

Concept

A backup contains the status, configuration, and data of a cloud server or disk stored at a specific time point for recovery in case of a fault. It is used to ensure data security and improve availability.

An image provides all information required for starting a cloud server. It is used to create a cloud server and deploy software environments in batches. A system disk image contains an OS and pre-installed application software for running services. A data disk image contains service data. A full-ECS image contains data of the system disk and data disks.

Usage method
  • Data storage location: Unlike server or disk data, backups are stored in OBS. Deleting a disk will not clear its backups.
  • Operation object: A server or disk can be backed up at a given point in time. CBR supports automatic backup and automatic deletion by configuring backup policies.
  • Usage: Backups can be used to restore data to the original server or disk, or to create a new disk or full-ECS image.
  • Support exporting to a local PC: No
  • Data storage location: Unlike server or disk data, backups are stored in OBS. If a server or disk that is created using an image is deleted, the image will not be cleared.
  • Operation object: The system disk and data disks of a server can be used to create private images. You can also create private images using external image files.
  • Usage: System disk images or full-ECS images can be used to create new servers, and data disk images can be used to create new disks for service migration.
  • Support exporting to a local PC: Yes However, full-ECS images cannot be exported to a local PC.

Application scenarios
  • Data backup and restoration
  • Rapid service deployment and migration
  • Server migration to the cloud or between clouds
  • Deploying a specific software environment
  • Deploying software environments in batches
  • Backing up server operating environments

Advantages

Supports automatic backup. Data on a server or disk at a certain time point can be retained periodically or quantitatively. You can back up on-premises VMware VMs, synchronize the backups to the cloud, and then use the backups to restore data to new ECSs.

Supports system disk backup. You can import the data disk image of a local server or a server provided by another cloud platform to IMS and then use the image to create an EVS disk.

Although backups and images are stored in OBS, you cannot view backup and image data in OBS, because they do not occupy your resources. Backup fees are charged according to the CBR billing standards, and image storage fees are charged according to the OBS billing standards.

Relationship Between Backups and Images

  1. You can use an ECS backup to create a full-ECS image.
  2. Before creating a full-ECS image for an ECS, you need to back up the target ECS.
  3. A backup is compressed when it is used to create an image, so the size of the generated image may be smaller than the backup size.
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