Every class I teach something interesting comes from the students in the class, so I thought I’d start to share these.
Last week I taught in Auckland and early on in the course we discussed VMware converter and the HAL that ends up in the converted VM. Two students used converter to do online conversions in order to minimise downtime, as you may know I don’t like online conversion & always use the boot CD.
One student had converted some terminal servers and the resulting VMs would redline the CPU all day. The original physical servers had dual PIII CPU’s so the single 2.6 GHz vCPU should have outperformed the old system. It turned out that converter hadn’t replaced the ACPI Multiprocessor HAL with the ACPI UniProc HAL. When the HAL was changed the CPU utilisation on the VMs dropped back to a sensible 20% rather than the stupid 100% that occurred with the wrong HAL.
Be warned that the converter does not change HAL, even if using offline conversion, if you are converting from SMP to non-SMP you will need to change the HAL. For more information take a look at the Microsoft support site
I’m having a couple of weeks off teaching, more notes from class should come through in June.
© 2007, Alastair. All rights reserved.