Vista - Defrag inside a VM. Would there be any point?

Would it help a VM if you were to run Defrag inside it? It's only a
virtual hard drive, but presumably it has the potential to fragment
itself within.

"d d" <go_on_try_and_sp@xxxxxx_me.com> wrote in message
news:O3NHG%233RJHA.1164@xxxxxx
As much as it would help any other machine, whether physical or virtual...
Not as far as the operating system running on it is concerned, which has not
the slightest idea that it's running in a virtual machine...
Correct.


--
Mark Rae
ASP.NET MVP
http://www.markrae.net

Mark Rae [MVP] wrote:Thanks Mark. I thought it would help but considered there might be some
reason I'd overlooked why it would be a ridiculous idea :-)

"d d" <go_on_try_and_sp@xxxxxx_me.com> wrote in message
news:%23ZuM%23K4RJHA.4680@xxxxxx
Generally speaking, whenever you have a VPC question, the answer is almost
always "what if this were a physical machine?". As mentioned, the software
(both operating system and applications) you install on a VM has not the
slightest idea that it's not running on a physical machine - it has no need
to know this, because it makes absolutely no difference.

Just consider every virtual machine as functionally equivalent to a
low-specification physical machine, and you'll not go far wrong.

Also: http://vpc.visualwin.com/ngfaq.aspx


--
Mark Rae
ASP.NET MVP
http://www.markrae.net

If you do a lot of install/uninstall of programs for testing purposes the VM
(physical size on disk) seems to grow in size. To solve for this condition
you need to empty the recycle bin (or use CCleaner to get out the crud) and
then defragment. You can then prepare the VM for compaction (use the virtual
disk precompactor from with VM Additions).

After you close down the VM you can use the Virtual Disk Wizard to compact
the VM. I have seen the physical size of the VM decrease by 2-4 gig in
physical size and the aftermath is that the VM seems a bit more responsive
when I again use that particular VM.

--

Richard Urban
Microsoft MVP
Windows Desktop Experience


"d d" <go_on_try_and_sp@xxxxxx_me.com> wrote in message
news:O3NHG%233RJHA.1164@xxxxxx

In message <#6xpEh4RJHA.2268@xxxxxx> "Mark Rae [MVP]"
<mark@xxxxxx> was claimed to have wrote:
True, but there is a little more to the defragmentation picture.
Defragmenting in the guest alone is worthless if the VHD file on the
host is fragmented as the physical heads will still need to seek for a
consecutive read.

To have an effect you must defragment within the guest first, then if
you're using an expanding VHD rather then a fixed size compact, then
finally defragment at least that one VHD file if not the entire drive.

As much as many questions start with "what if this were a physical
machine", you have to remember that you're combining the limitations of
the physical machine with the overhead of a virtual environment.

That being said, I would highly recommend defragmenting VMs, the
performance improvement can be staggering especially if you're on a
slower hard drive (a laptop, for example)

"d d" <go_on_try_and_sp@xxxxxx_me.com> wrote in message
news:O3NHG%233RJHA.1164@xxxxxxIt doesn't know that it is a virtual machine so, of course, it needs
defragging. I didn't realize though that VPC won't tell you when to defrag?
VMWare Workstation pops up a notice when you need to defrag. XP only needs
defragging about two-three times a year and I would assume Vista is about
the same. (Nothing like 98SE)!

"DevilsPGD" <spam_narf_spam@xxxxxx> wrote in message
news:t461i4dio980l66ufjtjgmvc7l9uj8khqd@xxxxxx
I took that as read. Surely everyone defragments their host machine on a
regular basis, no...?
Obviously.
Indeed.
Glad to hear it...


--
Mark Rae
ASP.NET MVP
http://www.markrae.net

In message <uz7btzESJHA.4772@xxxxxx> "Mark Rae [MVP]"
<mark@xxxxxx> was claimed to have wrote:
Prior to Vista, no, at least not if my consulting experience is of any
indicator. You'll get a few whiz kid types that like to maintain their
own systems and defragment compulsively, a few that remember they're
supposed to defragment but don't get around to it more then a handful of
times per year and the rest probably don't bother at all.

Vista defragments automatically, which is a step in the right direction.

To see how poorly defragmenting is understood just look around at less
technical forums where defragmenting seems to be understood to be less
about performance, instead you'll see "you should defragment in the
future to avoid this" coming up in response to problems that are solved
using chkdsk or even are as a result of bad hardware.
Well, obvious if you know how VHDs work. Of course those who know much
about the internal structure of a VHD probably know the answer to the
original question that started this thread anyway.

The reason I mention compacting too is that without compacting,
defragmenting inside the guest and in the host still results in
fragmentation internal to the VHD. If the goal is to defragment you
really need to perform all three steps and so far this thread had only
really discussed defragmenting within the VM itself, which is the first
step, but a borderline useless step on it's own.

On Sun, 16 Nov 2008 14:26:26 -0800, DevilsPGD
<spam_narf_spam@xxxxxx> wrote:
How do you defragment a single file?
I have never seen that option in the Windows defragmenter.

--

Bo Berglund (Sweden)