6.0

A snapshot preserves the following information:
n
Virtual machine seings. The virtual machine directory, which includes the disks added or changed
after you take the snapshot.
n
Power state. The virtual machine can be powered on, powered o, or suspended.
n
Disk state. State of all the virtual machine's virtual disks.
n
(Optional) Memory state. The contents of the virtual machine's memory.
The Snapshot Hierarchy
The Snapshot Manager presents the snapshot hierarchy as a tree with one or more branches. Snapshots in
the hierarchy have parent to child relationships. In linear processes, each snapshot has one parent snapshot
and one child snapshot, except for the last snapshot, which has no child snapshot. Each parent snapshot can
have more than one child. You can revert to the current parent snapshot or restore any parent or child
snapshot in the snapshot tree and create more snapshots from that snapshot. Each time you restore a
snapshot and take another snapshot, a branch, or child snapshot, is created.
Parent Snapshots
The rst virtual machine snapshot that you create is the base parent
snapshot. The parent snapshot is the most recently saved version of the
current state of the virtual machine. Taking a snapshot creates a delta disk
le for each disk aached to the virtual machine and optionally, a memory
le. The delta disk les and memory le are stored with the base .vmdk le.
The parent snapshot is always the snapshot that appears immediately above
the You are here icon in the Snapshot Manager. If you revert or restore a
snapshot, that snapshot becomes the parent of the You are here current state.
N The parent snapshot is not always the snapshot that you took most
recently.
Child Snapshots
A snapshot of a virtual machine taken after the parent snapshot. Each child
snapshot contains delta les for each aached virtual disk, and optionally a
memory le that points from the present state of the virtual disk (You are
here). Each child snapshot's delta les merge with each previous child
snapshot until reaching the parent disks. A child disk can later be a parent
disk for future child disks.
The relationship of parent and child snapshots can change if you have multiple branches in the snapshot
tree. A parent snapshot can have more than one child. Many snapshots have no children.
I Do not manually manipulate individual child disks or any of the snapshot conguration les
because doing so can compromise the snapshot tree and result in data loss. This restriction includes disk
resizing and making modications to the base parent disk by using vmkfstools.
Snapshot Behavior
Taking a snapshot preserves the disk state at a specic time by creating a series of delta disks for each
aached virtual disk or virtual RDM and optionally preserves the memory and power state by creating a
memory le. Taking a snapshot creates a snapshot object in the Snapshot Manager that represents the virtual
machine state and seings.
Chapter 3 Virtual Machine Management with the VMware Host Client
VMware, Inc. 73