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Cloud Backup:System resource requirements for backup

Last Updated:Apr 21, 2026

Operations that require a backup client—such as ECS file backup, local file backup, on-premises NAS backup, CPFS backup, archiving, and data synchronization—and virtual machine backup, which requires a backup gateway, have specific requirements for compute resources (such as vCPU and memory) and disk space. Evaluate your business scale and data volume to provision sufficient resources.

Compute resources

Important
  • The values in the following table are the minimum memory requirements for a single task in a lab environment. Actual memory usage varies depending on file distribution, file count, and file size.

  • To prevent an impact on your production services, the backup task intentionally fails if memory is insufficient.

Backup type

vCPUs

Minimum reserved memory

On-premises NAS backup

4

8 GB

CPFS backup

4

8 GB

Archive

4

8 GB

Data synchronization

4

8 GB

Local file backup

2

4 GB

ECS file backup

2

4 GB

Basic ECS file backup

High priority

2

4 GB

Low priority

1

128 MB

Virtual machine backup

4

16 GB

Disk space

Note

The meaning of "backup node disk" varies by scenario. In on-premises-to-cloud scenarios (such as backing up, archiving, or synchronizing data from a local server), it refers to the local server's hard disk. In cloud scenarios (such as ECS instance file backup, CPFS backup, cloud archiving, or cloud synchronization), it refers to the ECS instance's block storage, which includes local disks and cloud disks.

On-premises NAS backup/CPFS backup/archive/data synchronization

Reserve 1 GB of space for installing the backup client (including the installation package and temporary logs).

Local file backup/ECS file backup/Basic ECS file backup

When you back up files from an on-premises server or an ECS instance, the backup client installation and runtime cache consume disk space on the backup node. Reserve sufficient space on the disk where the backup client is installed.

  • Space required to install the backup client (including the installation package and temporary logs): 1 GB.

  • Backup runtime cache space: This cache stores backup metadata to accelerate backups. Cloud Backup requires the backup node disk to have at least 1 GB of free space. If you back up more than one million files, reserve an additional 0.5 GB of space for each additional million files.

    Important

    If the remaining disk space drops below 1 GB, the file backup fails with an "insufficient space" error.

The recommended reserved disk space is the sum of the space required to install the backup client and the backup runtime cache space. The required space depends on the number of files to be backed up. The required space can be approximated with the following formula: 1 GB + 1 GB + 0.5 GB × ⌈number of files/1,000,000⌉. The following table provides examples.

Number of files

Recommended disk space (GB)

2 million

3 GB

5 million

4.5 GB

10 million

7 GB

Virtual machine backup

The disk space required for virtual machine backup depends on the disk provisioning mode.

  • Virtual machine (thin provisioning): 12.7 GB.

  • Virtual machine (thick provisioning): 100.0 GB.