Considerations For Running Multiple Virtual Machines Part III

In the previous installment of this article, I outlined some of the specific settings you need to pay attention to when running multiple VMs with Virtual Server 2005 R2. In Part III of this series, we’ll continue looking at various settings that may require your attention.

Video Settings
Since each guest operating system runs independent of each other, each one can be configured with different video resolution settings. This will have a slight impact on performance as you switch between virtual machines running simultaneously. It will take a few seconds for Virtual Server to change to the correct resolution settings as you switch between virtual machines.

Com and Parallel Ports
Any devices attached to the host’s COM port are accessible under a guest operating system. If you plan to run multiple virtual machines, keep in mind that any device attached to a COM port is only accessible to one virtual machine at a time. If you want to use the device under another guest operating system, the other virtual machine must first release the COM port (you can accomplish this by shutting the VM down).

As with COM ports, any devices that are attached to the parallel (LPT1) port are only accessible by one virtual machine at a time. No other guest operating system, or the host operating system, will be able to use the device until the virtual machine is shut down.

Floppy Drives
Each virtual machine is configured with a single floppy drive. You can configure a virtual machine’s floppy drive to use either a physical floppy disk drive or a virtual floppy disk (vfd) file.

A virtual floppy disk file can be shared between multiple virtual machines, if the file has been marked as read-only. In the case of a physical floppy disk, this can only be used by one virtual machine at a time.

Tip: If you have multiple virtual machines that are configured to start automatically, consider altering the properties of each one to stagger the start times. By configuring the Seconds to delay automatically starting a virtual machine option, you can prevent the virtual machines from starting at exactly the same time and thereby reduce the demand placed on the host computer’s physical resources.

[tags]virtual machine, networking[/tags]