Constraints

General

• A vault can be associated with only one backup policy.
• A vault can be associated with a maximum of 256 resources.
• A maximum of 32 backup policies can be created.
• Only backups in the Available or Locked vaults can be used to restore data.
• Backups in a Deleting vault cannot be deleted.
• Backups cannot be downloaded to a local PC or uploaded to OBS.
• A vault and its associated servers or disks must be in the same region.
• Concurrent data restoration is not supported.
• Auto capacity expansion does not take effect if it is enabled after the vault is full.

Cloud Disk Backup

• Only disks in the Available or In-use state can be backed up.
• Frozen disks in the retention period cannot be backed up.
• A new disk must be at least as large as the backup's source disk.
• Backup and restoration of local disks are not supported.

Cloud Server Backup

• A maximum of 10 shared disks can be backed up with a cloud server.
• Only backups in the Available or Locked vaults can be used to create images.
• Frozen servers in the retention period cannot be backed up.
• Cloud servers support crash-consistent backup, whereas database servers support application-consistent backup in addition to crash-consistent backup.
• You can back up specific disks on a server, but such a backup must be restored as a whole. File- or directory-level restoration is not supported.
• Images cannot be created from backups if the amount of resources associated with a server backup vault exceeds the quota.
• You are advised not to back up a server whose disk size exceeds 4 TB.

SFS Turbo Backup

• Only file systems in the Available state can be backed up.
• An SFS Turbo file system backup cannot be used to restore data to the original file system.

Hybrid Cloud Backup - VMware Backup

• VM backups from the following VMware vSphere versions can be restored to cloud servers: 5.1, 5.5, 6.0, 6.5. If you do not need to restore the backups to cloud servers, there is no restriction on the VMware version.
• To obtain better performance and operation experience, you are advised to use the OSs listed in Table 1, which have passed the compatibility test.
• The VDDK version of VMware 6.5 VMs must be 6.0.3.
• Backups synchronized to the cloud cannot be used to create cloud servers.
• Backups synchronized to the cloud can only be restored to other cloud servers running the same OS, and can be restored to system disks or data disks.
• Servers whose system disks are configured with LVM cannot be restored on cloud.
• Before the restoration, configure security groups according to the procedure. Otherwise, the restoration may fail.

  Table 1 OSs that support restoration to the cloud

  OS	Supported Version
  Windows	Windows 7 Windows Server 2008 R2 Windows Server 2012 Windows Server 2012 R2 Windows Server 2016 Windows Server 2019
  CentOS	CentOS 6.4 CentOS 6.5 CentOS 7.2 CentOS 7.3 CentOS 7.4 CentOS 7.5 CentOS 7.6 CentOS 7.7
  Red Hat	Red Hat 6.4 Red Hat 6.5 Red Hat 7.2

Application-Consistent Backup