How to change from ACPI Multiprocessor HAL back to ACPI Uniprocessor HAL in Windows 2003

Posted on January 9th, 2009 webmaster 4 comments          Print

“Warning: Changing the number of virtual processors after the guest OS is installed may make your virtual machine unstable.”

You’ve probably seen this message before while working with VMware, especially if you’ve done physical to virtual migrations.

As a best practice, it is recommended to always start with only 1 vCPU when creating virtual machines and only increase the number of vCPUs if you think it’s necessary and if the virtual machine is actually running applications that can utilize multiple processors to avoid wasting resources.

Increasing the number of processors from 1 to 2 or more is actually not a problem with Windows Server 2003 because it will automatically change the HAL to ACPI Multiprocessor PC.  But setting the number of virtual processors back to 1 won’t automatically change the Windows 2003 HAL back to ACPI Uniprocessor PC.

According to Microsoft, “If you run a multiprocessor HAL with only a single processor installed, the computer typically works as expected, and there is little or no affect on performance.”  But if you’re like me and just want to be absolutely sure that there won’t be issues, switching back to the uniprocessor HAL in Windows Server 2003 is pretty easy:

1. Make sure you have at least Windows Server 2003 Service Pack 2 installed.
2. Shut down the virtual machine.
3. Change number of virtual processors to 1.
4. Power on the virtual machine.
5. In Windows, go to Device Manager -> Computer.
6. Right-click “ACPI Multiprocessor PC” and choose “Update Driver…“.
7. Select “No, not this time” option -> “Install from a list or specific location” -> “Don’t search.  I will choose the driver to install.” -> select “ACPI Uniprocessor PC.”
8. Reboot the virtual machine.

That’s it! You’re all set!

getVIRTUALnow

Posted on November 3rd, 2008 webmaster No comments          Print

Just got back from the Microsoft Virtualization Launch Event in New York.  Overall, it was pretty good.  It was also pretty short, it started at 8:30am and it’s pretty much done by 1:30pm.  There’s also not a lot of people who attended this event compared to their other launch events, there were plenty of seats available.

They pretty much talked mostly about the benefits of virtualization and Microsoft System Center.  They showed live demos on how to use System Center and its interoperability with VMware ESX Server.  They also showed demos for application virtualization and there are hands on labs if you want to try out the products.

For the free stuff, you get a T-Shirt, a voucher for prep course collection #6319 and exam #70-652 ($316 value), and a Microsoft Virtualization Evaluation Kit (will be mailed to you).

VMware ESXi: Setup did not find any hard disk drives installed in your computer (Windows XP)

Posted on October 23rd, 2008 webmaster 20 comments          Print

Error Message:

Setup did not find any hard disk drives installed in your computer.

If you get this error when installing Windows XP in VMware ESXi, simply do the following:

1. Download this floppy image which contains the VMware SCSI drivers: vmscsi-1.2.0.4.flp.
2. Upload the floppy image to the datastore using the VI Client.
3. Edit the virtual machine settings and select Floppy Drive 1, then choose the option on the right to “Use existing floppy image in datastore:” and select the floppy image.
4. Power on the virtual machine.
5. Press F6 when you see the message “Press F6 if you need to install a third party SCSI or RAID driver…” at the bottom of the screen.
6. Connect Floppy Drive 1.
7. Press S, then press Enter to select the VMware SCSI Controller driver, then press Enter again to continue with the setup.

That’s it! The Windows XP setup should now be able to detect the hard drives .

Source: VMware Knowledgebase Document