Microsoft Hyper-V Vss Writer Backup Specifics - HP Data Protector A.06.11 Integration Manual

Microsoft Hyper-V VSS writer backup specifics

With the Hyper-V VSS writer, it is possible to back up:
• The Hyper-V configuration
• Virtual machines
The following two types of backups are supported by the Data Protector VSS
integration:
• Online backup
Online backup of Hyper-V writer data is possible using a software provider or
hardware provider.
If using a hardware provider for an online backup process, Hyper-V writer creates
a shadow copy, which is replicated together with the vhd file via the VSS hardware
provider. Afterwards, the shadow copy is presented to the Hypervisor System. In
the case of transportable backup, the shadow copy is afterwards unpresented
from the Hypervisor System and presented to the backup system, specified in the
backup specification.
After restore of an online backup session, the virtual machine is always turned
off, regardless of the state in which it was before the restore.
• Offline backup
Offline backup is performed in the following cases:
• The guest operating system – any other non-Microsoft guest operating system
that is supported by Hyper-V – is not VSS enabled.
• The guest operating system does not have Hyper-V VSS integration services
installed.
• The virtual machine to be backed up is turned off.
Before offline backup, the virtual machine is automatically suspended (if not
already) and resumed after the backup.
After restore of an offline backup session, the virtual machine is suspended,
regardless of the state it was in before the restore.
The advantage of offline backup is that virtual machines are restored to the state
they were in at backup time, including the state of applications running at the
time of backup. This is possible because a virtual machine is in a suspended state
during the backup.
Prerequisites
• For online backup:
Zero downtime backup integration guide 375