====== Backup Methods ======
----
CloudBacko Pro supports two methods for Hyper-V guest VM backup, VM Snapshot and Saved State.

{{INLINETOC}} \\

===== VM Snapshot =====
----

The VM snapshot method is the preferred backup option, as it supports live guest VM backups. This means guest VM will not be put into a saved state when a VSS snapshot is taken during a backup job. So it will not affect the availability of any applications or services running on the guest VM every time a backup job is performed.

<WRAP info>If the VM Snapshot method cannot be used, CloudBacko Pro will automatically use the Saved State method. </WRAP>

<WRAP indent>
==== Requirements ====
----

1. The guest VM must be running.

2. Integration services must be enabled on the guest VM.

3. The Hyper-V Volume Shadow Copy Requestor service is running on the guest VM installed with Windows operating system. Please refer to the following article for further details: [[https://docs.microsoft.com/en-us/virtualization/hyper-v-on-windows/reference/integration-services#hyper-v-volume-shadow-copy-requestor]]

4. For guest VMs installed with Linux / FreeBSD operating systems, the VSS Snapshot daemon is required for live backups, not all Linux / FreeBSD versions support live backup on Hyper-V. For example, only FreeBSD 11.1 supports live backup while for Ubuntu, version 14.04 LTS to 17.04 LTS supports live backups. Please refer to the following article for further details: [[https://docs.microsoft.com/en-us/windows-server/virtualization/hyper-v/supported-linux-and-freebsd-virtual-machines-for-hyper-v-on-windows]]

5. The guest VM volumes must use a file system which supports the use of VSS snapshots, for example NTFS.

6. The guest VMs snapshot file location must be set to the same volume in the Hyper-V host as the VHD file(s).

7. The guest VM volumes have to reside on basic disks. Dynamic disks cannot be used within the guest VM.
<WRAP info>Some older Windows operating systems installed on guest VM's which do not support either Integration Services or the Hyper-V Volume Shadow Copy Requestor Service, will not support VM snapshot method, for example, Microsoft Windows 2000, Windows XP, or o lder Linux/FreeBSD versions. </WRAP>
</WRAP>

\\

===== Saved State =====
----
If any of the VM Snapshot method requirements cannot be fulfilled, CloudBacko Pro will automatically use the Save State method. When the Saved State method is used, the guest VM is placed into a saved state while the VSS snapshot is created (effectively shut down), and the duration is dependent on the size of VM and performance of Huper-V host. The downside is it may affect the availability of any applications or services running on the guest VM every time a backup job is performed.