Installation guide

3 Click Delete to permanently remove a snapshot from vCenter Server.
Clicking Delete Allpermanently removes all snapshots from the virtual machine.
NOTE Delete commits the snapshot data to the parent and removes the selected snapshot. Delete All
commits all the immediate snapshots before the You are here current state to the base disk and removes
all existing snapshots for that virtual machine. When using the Delete All option in Snapshot Manager,
the snapshot farthest from the base disk is committed to its parent, causing that parent snapshot to grow.
When that commit is complete, that snapshot is removed and the process starts over on the newly updated
snapshot to its parent. This continues until every snapshot has been committed. This method can be
relatively slow since data farthest from the base disk might be copied several times. More importantly,
this method can aggressively use disk space if the snapshots are large, which is especially problematic if
a limited amount of space is available on the datastore. The space issue is troublesome in that you might
chose to delete snapshots explicitly to free up storage. This issue is resolved in ESX 4.0 Update 2 in that
the order of snapshot consolidation has been modified to start with the snapshot closest to the base disk
instead of farthest. The end result is that copying data repeatedly is avoided.
4 Click Yes in the confirmation dialog box.
Restore a Snapshot
To return a virtual machine to its original state, you can restore a snapshot.
Do one of the following:
Procedure
n
The Inventory > Virtual Machine > Snapshot menu contains the command Revert to Snapshot.
n
The Snapshot Manager has a Go to button.
Parent Snapshot
The parent snapshot is the most recently saved version of the current state of the virtual machine.
If you have just taken a snapshot, that stored state is the parent snapshot of the current state (You are here). If
you revert or go to a snapshot, that snapshot becomes the parent of the current state (You are here).
The parent snapshot is always the snapshot appearing immediately above the You are here icon in the Snapshot
Manager.
NOTE The parent snapshot is not always the snapshot you took most recently.
Revert to Snapshot Command
Reverting snapshots immediately activates the parent snapshot of the current state of the virtual machine.
The current disk and memory states are discarded and restored as they were when you took that snapshot. If
your parent snapshot was taken when the virtual machine was powered off, choosing Snapshot > Revert to
Snapshot moves the powered-on virtual machine to that parent state, that is, to a powered-off state.
If the snapshot was taken while the virtual machine was powered on and the virtual machine settings are set
to revert to snapshot when powering off, the virtual machine moves to a suspended state when it reverts to
the parent snapshot. If the no memory option is set, the virtual machine moves to a suspended state, even if
the revert operation is performed, but not through the powered-off action. If the memory option is set, the
power-off revert action puts the virtual machine in a suspended state. This process is illustrated in
Figure 17-1.
NOTE Virtual machines running certain kinds of workloads might take several minutes to resume
responsiveness after reverting from a snapshot. This delay may be improved by increasing the guest memory.
Chapter 17 Using Snapshots
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