RE: Very slow performance on Dell PE4600

On Fri, 10 Oct 2008 09:46:43 -0700, "Steve Jain [MVP]"
<noreply.-@-.essjae.com> wrote:


>Are you trying to install on IDE or SCSI virtual hard drive. If
>you're doing it on SCSI you need to install the SCSI driver at the F6
>prompt, otherwise your install with take hours.
>The drivers are included on a .VFD in the VM Additions folder.
>IDE doesn't have this problem, you can always switch from IDE to SCSI
>after the installation.

Do you mean that the VHD file format is the same irrespective of the
IDE/SCSI setting on the guest? So that one can use a VHD created as a
SCSI disk also as an IDE disk if one changes the properties in the
guest???

--

Bo Berglund (Sweden)

>Do you mean that the VHD file format is the same irrespective of the
>IDE/SCSI setting on the guest? So that one can use a VHD created as a
>SCSI disk also as an IDE disk if one changes the properties in the
>guest???

Yes. Though your OS may not boot just changing things like that. (OS
problem with drivers and boot info, not a VM problem.)

--
Bob Comer




On Sat, 11 Oct 2008 06:22:23 +0200, Bo Berglund <boberglund@home.se>
wrote:

>On Fri, 10 Oct 2008 09:46:43 -0700, "Steve Jain [MVP]"
><noreply.-@-.essjae.com> wrote:
>
>
>>Are you trying to install on IDE or SCSI virtual hard drive. If
>>you're doing it on SCSI you need to install the SCSI driver at the F6
>>prompt, otherwise your install with take hours.
>>The drivers are included on a .VFD in the VM Additions folder.
>>IDE doesn't have this problem, you can always switch from IDE to SCSI
>>after the installation.
>
>Do you mean that the VHD file format is the same irrespective of the
>IDE/SCSI setting on the guest? So that one can use a VHD created as a
>SCSI disk also as an IDE disk if one changes the properties in the
>guest???

On Sat, 11 Oct 2008 09:19:25 -0400, Robert Comer
<bobcomer-removeme-@mindspring.com> wrote:

>>Do you mean that the VHD file format is the same irrespective of the
>>IDE/SCSI setting on the guest? So that one can use a VHD created as a
>>SCSI disk also as an IDE disk if one changes the properties in the
>>guest???
>
>Yes. Though your OS may not boot just changing things like that. (OS
>problem with drivers and boot info, not a VM problem.)

So if I set up a guest in VPC2007 (thus using IDE disk emulation) and
then want to run this in a VS2005 scenario, I can create a new VS
guest and point it to this VHD while telling VS2005 that the disk is a
SCSI drive (the default)?

I have migrated VPC2007 guests to VS2005 before but I always modified
the defaults from SCSI to IDE as the disk type.
Was this unnecessary?

--

Bo Berglund (Sweden)

>So if I set up a guest in VPC2007 (thus using IDE disk emulation) and
>then want to run this in a VS2005 scenario, I can create a new VS
>guest and point it to this VHD while telling VS2005 that the disk is a
>SCSI drive (the default)?

If the OS can handle the drivers and boot info, yep. You'll have to
make sure the SCSI Shunt driver gets loaded for good performance.

>I have migrated VPC2007 guests to VS2005 before but I always modified
>the defaults from SCSI to IDE as the disk type.
>Was this unnecessary?

It depends on the guest.

Remember that not all OS's have additions and those that don't will be
slower without the SCSI Shunt driver. And then there's the boot info
-- most likely it would be okay with a modern OS.

FWIW, Hyper-V requires the boot VHD to be IDE and the performance
difference is negligible with Hyper-V between SCSI and IDE.

--
Bob Comer


On Sat, 11 Oct 2008 16:49:06 +0200, Bo Berglund <boberglund@home.se>
wrote:

>On Sat, 11 Oct 2008 09:19:25 -0400, Robert Comer
><bobcomer-removeme-@mindspring.com> wrote:
>
>>>Do you mean that the VHD file format is the same irrespective of the
>>>IDE/SCSI setting on the guest? So that one can use a VHD created as a
>>>SCSI disk also as an IDE disk if one changes the properties in the
>>>guest???
>>
>>Yes. Though your OS may not boot just changing things like that. (OS
>>problem with drivers and boot info, not a VM problem.)
>
>So if I set up a guest in VPC2007 (thus using IDE disk emulation) and
>then want to run this in a VS2005 scenario, I can create a new VS
>guest and point it to this VHD while telling VS2005 that the disk is a
>SCSI drive (the default)?
>
>I have migrated VPC2007 guests to VS2005 before but I always modified
>the defaults from SCSI to IDE as the disk type.
>Was this unnecessary?

"Robert Comer" <bobcomer-removeme-@mindspring.com> wrote in message
news:2vh1f4hf8p17oq0qbrrtm903snog3u9eqn@4ax.com...
>>So if I set up a guest in VPC2007 (thus using IDE disk emulation) and
>>then want to run this in a VS2005 scenario, I can create a new VS
>>guest and point it to this VHD while telling VS2005 that the disk is a
>>SCSI drive (the default)?
>
> If the OS can handle the drivers and boot info, yep. You'll have to
> make sure the SCSI Shunt driver gets loaded for good performance.
>
>>I have migrated VPC2007 guests to VS2005 before but I always modified
>>the defaults from SCSI to IDE as the disk type.
>>Was this unnecessary?
>
> It depends on the guest.
>
> Remember that not all OS's have additions and those that don't will be
> slower without the SCSI Shunt driver. And then there's the boot info
> -- most likely it would be okay with a modern OS.
>
> FWIW, Hyper-V requires the boot VHD to be IDE and the performance
> difference is negligible with Hyper-V between SCSI and IDE.
>
> --
> Bob Comer
>
>
> On Sat, 11 Oct 2008 16:49:06 +0200, Bo Berglund <boberglund@home.se>
> wrote:
>
>>On Sat, 11 Oct 2008 09:19:25 -0400, Robert Comer
>><bobcomer-removeme-@mindspring.com> wrote:
>>
>>>>Do you mean that the VHD file format is the same irrespective of the
>>>>IDE/SCSI setting on the guest? So that one can use a VHD created as a
>>>>SCSI disk also as an IDE disk if one changes the properties in the
>>>>guest???
>>>
>>>Yes. Though your OS may not boot just changing things like that. (OS
>>>problem with drivers and boot info, not a VM problem.)
>>
>>So if I set up a guest in VPC2007 (thus using IDE disk emulation) and
>>then want to run this in a VS2005 scenario, I can create a new VS
>>guest and point it to this VHD while telling VS2005 that the disk is a
>>SCSI drive (the default)?
>>
>>I have migrated VPC2007 guests to VS2005 before but I always modified
>>the defaults from SCSI to IDE as the disk type.
>>Was this unnecessary?

I transferred a few vhds from VPC to Virtual Server IDE and then to
SCSI.

From memory I think the best plan is to add the SCSI adapter but boot up
as IDE. Then add the vmadditions to load the SCSI driver. You can then
allocate the vhd to the SCSI interface and boot from it.