Setting Up Desktop and Application Pools in View

Table 3‑9. Impact of Windows 7 and Windows 8 Services and Tasks on OS Disk Growth and IOPS When OS Is Left
Idle
Service or Task Description
Default
Occurrence or
Startup
Impact on
Linked-Clone OS
Disks Impact on IOPS
Turn Off This
Service or Task?
Windows
Hibernation
Provides a power-
saving state by
storing open
documents and
programs in a file
before the
computer is
powered off. The
file is reloaded
into memory when
the computer is
restarted, restoring
the state when the
hibernation was
invoked.
Default power-
plan settings
disable
hibernation.
High.
By default, the size
of the hibernation
file,
hiberfil.sys, is
the same as the
installed RAM on
the virtual
machine. This
feature affects all
guest operating
systems.
High.
When hibernation
is triggered, the
system writes a
hiberfil.sys file
the size of the
installed RAM.
Yes
Hibernation
provides no benefit
in a virtual
environment.
For instructions, see
“Disable Windows
Hibernation in the
Parent Virtual
Machine,” on
page 49..
Windows
Scheduled Disk
Defragmentation
Disk
defragmentation is
scheduled as a
background
process.
Once a week High.
Repeated
defragmentation
operations can
increase the size of
linked-clone OS
disks by several
GB and do little to
make disk access
more efficient on
linked clones.
High Yes
Windows Update
Service
Detects,
downloads, and
installs updates for
Windows and
other programs.
Automatic startup Medium to high.
Causes frequent
writes to the
linked-clones' OS
disks because
update checks
occur often. The
impact depends on
the updates that
are downloaded.
Medium to high Yes, if you use View
Composer
recompose to install
Windows updates
and refresh to
return OS disks to
their original
snapshots.
Windows
Diagnostic Policy
Service
Detects,
troubleshoots, and
resolves problems
in Windows
components. If
you stop this
service,
diagnostics no
longer function.
Automatic startup Medium to high.
The service is
triggered on
demand. The write
frequency varies,
depending on
demand.
Small to medium Yes, if you do not
need the diagnostic
tools to function on
the desktops.
Prefetch/Superfetch Stores specific
information about
applications that
you run to help
them start faster.
Always on, unless
it is disabled.
Medium
Causes periodic
updates to its
layout and
database
information and
individual
prefetch files,
which are
generated on
demand.
Medium Yes, if application
startup times are
acceptable after you
disable this feature.
Chapter 3 Creating and Preparing Virtual Machines
VMware, Inc. 41