Vista - Estimate time to convert virtual disk to fixed size?

In Vista Business 64-bit host I have VPC 2007 guest running Windows XP with
virtual hard drive of current size 35Gb (Max size 64Gb).

I decided to convert it to fixed size for possible performance gains.

1. Defragmented VHD from within Windows XP;
2. Compressed VHD from VPC 2007;
3. Defragmented file containing VHD from Vista (at this moment file had
3 fragments. There was ample free space on physical drive (>120Gb).
4. Started VM Wizard.

Several hours (> 12h)later I had to cancel this process. Physical file
(temporary file of .xxx extension and size of target drive (64 Gb) had over
150,000 fragments.

Q1. How long such conversion should take?
Q2. Would creation of fixed size empty disk in XP and use of imaging software
to copy XP old diks to new disk be faster?


Jan M. Nelken

1 and 2 really don't buy you much except more space on the host hard
drive. (that's if you have a 1.5 that says you ran the procompactor)

3 doesn't buy you anything as a new VHD is created and the old one
deleted.
The 12 hrs sounds high, but the fragments is just how NTFS works, when
you write to it, that's the way the system does. It does take a long
time and if your disk isn't that fast, 12 hrs probably isn't that
surprising.
It all depends on your hardware and size of virtual disk.
Maybe, but I kind of doubt it. You still have to create the fixed
disk and that takes a lot of time, and then you actually have to do
the image copy.

--
Bob Comer


On Sun, 25 Jan 2009 02:10:45 -0500, "Jan M. Nelken"
<Unknown.User@xxxxxx> wrote:

Robert Comer wrote:1,2,3 were primarly performed to have reads from old drive as fast as possible -
at least that was my concept...
Laptop with 5400 rpm SATA disk (Toshiba 250 Gb)

....
I was hoping that image copy may be faster than disk conversion...

Jan M. Nelken

>1,2,3 were primarly performed to have reads from old drive as fast as possible -Defragmenting actually doesn't do much for that unless the VM is
*heavily* fragmented. It's the writes that are the slowest operation
on a disk.

You could always do the defragment after the conversion to a fixed
disk.
My laptop has a similar drive, it's not very fast, and NTFS writing is
pretty slow. Do you have Write cache enabled on that drive, that may
help some.
It may be, but you still have to create the fixed disk, it takes quite
some time, so overall, I doubt it would be much faster, if any.

--
Bob Comer


On Sun, 25 Jan 2009 09:42:30 -0500, "Jan M. Nelken"
<Unknown.User@xxxxxx> wrote:

On Sun, 25 Jan 2009 02:10:45 -0500, "Jan M. Nelken"
<Unknown.User@xxxxxx> wrote:
Which gains would you expect?
As far as I know the main difference between a dynamically expanding
and a fixed VHD disk is that the fixed type allocates the full size of
the drive at once, which means that it would have to create a file on
the host with the same size as you specify for the drive and then
initialize all of the clusters as well. With a good sized disk (64 Gb
in your case) this would taka a rather long time even for a new empty
disk.
Add to this that you are *converting* an existing dynamic disk to
afixed disk with 35 Gb worth of data. Now the process would have to
move all of your data as well into the new drive. I don't think that
the conversion is done in situ so you will have to provide space on
your disk for all this to happen too. Do you have 64 Gb+ extra free
space on your drive?

I'd not expect this to be a quick process, especially not on a laptop
with limited disk resources. Expect a lot of disk head moves and a
good deal of fragmentation...
And of course set aside a lot of time...

After it is done you would probably like to defrag the VHD file on the
host (given that you have enough free space of course).
--

Bo Berglund (Sweden)

Bo Berglund wrote:Yes, there is ample room on this freshly acquired drive for old 35GB VHD, new
64Gb fixed VHD and about 100 Gb free space.
Creating a new 64 Gb drive took 45-90 minutes (cannot tell exactly as I stepped
out for a while.

However 2 different disk imaging freeware's jointly stopped after moving 4096 Mb
worth of data from old VHD to new fixed size VHD claiming disk is full.

May be I will dedicate long weekend for my last attempt to convert - but it
appears that more efficient approach is to trash old VFD, create new fixed size
VHD and reinstall all software.

I am not amused.


Jan M. Nelken

On Tue, 27 Jan 2009 12:36:36 -0500, "Jan M. Nelken"
<Unknown.User@xxxxxx> wrote:
I've used Norton Ghost with success in VHD to VHD transfers. I've had
poor experiences with freeware imaging apps also.

--
Cheers,
Steve Jain, Virtual Machine MVP
http://vpc.essjae.com/

On Tue, 27 Jan 2009 10:03:31 -0800, "Steve Jain [MVP]"
<noreply.-@-.essjae.com> wrote:
And I have also used Ghost but switched to Acronis because for newer
OS the restored image seems to be incompatible causing for example
Vista to request the original install disk to do some extra work after
the restored image is started.
Not so with Acronis.

--

Bo Berglund (Sweden)