What does a disk or volume backup store?

A disk or volume backup stores a disk or a volume file system as a whole and includes all of the information necessary for the operating system to boot. It is possible to recover disks or volumes as a whole from such backups as well as individual folders or files.

With the sector-by-sector (raw mode) backup option enabled, a disk backup stores all the disk sectors. The sector-by-sector backup can be used for backing up disks with unrecognized or unsupported file systems and other proprietary data formats.

Windows

A volume backup stores all files and folders of the selected volume independent of their attributes (including hidden and system files), the boot record, the file allocation table (FAT) if it exists, the root and the zero track of the hard disk with the master boot record (MBR).

A disk backup stores all volumes of the selected disk (including hidden volumes such as the vendor's maintenance partitions) and the zero track with the master boot record.

The following items are not included in a disk or volume backup (as well as in a file-level backup):

  • The swap file (pagefile.sys) and the file that keeps the RAM content when the machine goes into hibernation (hiberfil.sys). After recovery, the files will be re-created in the appropriate place with the zero size.

  • If the backup is performed under the operating system (as opposed to bootable media or backing up virtual machines at a hypervisor level):

    • Windows shadow storage. The path to it is determined in the registry value VSS Default Provider which can be found in the registry key HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\BackupRestore\FilesNotToBackup. This means that in operating systems starting with Windows Vista, Windows Restore Points are not backed up.
    • If the Volume Shadow Copy Service (VSS) backup option is enabled, files and folders that are specified in the HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\BackupRestore\FilesNotToSnapshot registry key.

Linux

A volume backup stores all files and directories of the selected volume independent of their attributes, a boot record, and the file system super block.

A disk backup stores all disk volumes as well as the zero track with the master boot record.

Mac

A disk or volume backup stores all files and directories of the selected disk or volume, plus a description of the volume layout.

The following items are excluded:

  • System metadata, such as the file system journal and Spotlight index
  • The Trash
  • Time machine backups

Physically, disks and volumes on a Mac are backed up at a file level. Bare metal recovery from disk and volume backups is possible, but the sector-by-sector backup mode is not available.