Azure Backup provides a host of services for disaster recovery:
- VM backup
- Storage backup
- Site Recovery
Backups can be configured to take place on a schedule or be taken on an ad hoc basis.
Recovery service vaults
Recovery service vaults provide the geo-redundant storage for the backed up data. They're replicated across paired regions to protect against the failure of entire Azure regions.
The only Azure Storage service natively supported by Azure Backup is Files, where each share can be configured as an independent backup item with its own backup policy and jobs.
Virtual machine backup is achieved at the block device (disk) level, and works by temporarily freezing all of the attached disks to snapshot them. This minimises the impact of the frequent backup operations as the differences between the disks can be calculated outside of the virtual machine, but comes at the expense of ease of restoration.
Restore VM operations can either:
- Restore VM: create a new VM from the snapshots of the disks at the selected point; or
- File Recovery: deallocate the VM and restore all the disks in-place.
File Recovery allows you to access a read-only copy of the disks at a given snapshot. The disks are made available as an iSCSI target and Azure generates a Python script which can be used to attach the disks and attempt to automatically mount the volumes.