The Bottom Line
Explain how backup works in a Hyper-V environment. Windows features
the VSS component that enables application-consistent backups to be taken of an
operating system by calling VSS writers created by application vendors. When a
backup is taken of a virtual machine at the Hyper-V host level, the VSS request is
passed to the guest operating system via the backup guest service, which allows the
guest OS to ensure that the disk is in a backup-ready state, allowing the virtual
hard disk to be backed up at the host and be application consistent.
Master It Is shared VHDX backed up when you perform a VM backup at the
host level?
Understand how to best use checkpoints and where not to use them.
Checkpoints, previously known as snapshots, allow a point-in-time view of a
virtual machine to be captured and then applied at a later time to revert the virtual
machine back to the state it was in at the time the snapshot was taken. Windows
Server 2016 introduced a new type of checkpoint, the production checkpoint.
Production checkpoints interact with the VSS infrastructure inside the guest OS
that provides an application-consistent checkpoint. Production checkpoints can be
used in production environments. Standard checkpoints that do not interact with
VSS and save the complete state of a VM, including memory, are useful in testing
scenarios but should not be used in production because the effect of moving a
virtual machine back in time without the OS knowledge can cause problems for
many services. It can even cause domain membership problems if the computer’s
AD account password changes after the checkpoint creation.
Understand the benefits of service templates. Typically, a virtual machine is
created from a virtual machine template, which allows a single virtual machine to
be deployed. A service template allows a complete, multitiered service to be
designed and then deployed through a single action. Additionally, each tier can be
configured to scale up and down as workloads vary, which enables additional
instances of the virtual machine for a tier to be created and deleted as necessary.
Deployed instances of a service template retain their relationship to the original
service template, which means that if the original service template is updated, the
deployed instances can be refreshed and updated with the service template
changes without losing application state.