Specifications

CHAPTER 6 Using Disks in a Virtual Machine
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way are similar to the experimental plain disks that could be created under earlier
versions of GSX Server.
A virtual disk that is not preallocated is known as a growable disk. A growable virtual
disk’s files start out small and grow to their maximum size as needed. The main
advantage of this approach is the smaller file size. Smaller files require less storage
space and are easier to move if you want to move the virtual machine to a new
location. You can shrink this type of virtual disk. However, it takes longer to write data
to a disk configured in this way.
Virtual disks can be set up as IDE disks for any guest operating system. They can be set
up as SCSI disks for any guest operating system that has a driver for the BusLogic SCSI
adapter used in a GSX Server virtual machine.
Note: To use SCSI disks in a Windows XP or Windows Server 2003 virtual machine,
you need a special SCSI driver available from the download section of the VMware
Web site at www.vmware.com/download. Follow the instructions on the Web site to
use the driver with a fresh installation of Windows XP or Windows Server 2003.
A virtual disk of either type can be stored on either type of physical hard disk. That is,
the files that make up an IDE virtual disk can be stored on either an IDE hard disk or a
SCSI hard disk. So can the files that make up a SCSI virtual disk. They can also be stored
on other types of fast-access storage media, such as DVD-ROM or CD-ROM discs. For
information about running virtual machines from DVD-ROM or CD-ROM, see Running
Virtual Machines from DVD-ROM or CD-ROM Discs on page 130.
A key advantage of virtual disks is their portability. Because the virtual disks are stored
as files on the host machine or a remote computer, you can move them easily to a
new location on the same computer or to a different computer. You can also use GSX
Server on a Windows host to create virtual disks, then move them to a Linux computer
and use them under GSX Server for Linux — or vice versa. For information about
moving virtual disks, see Moving and Sharing Virtual Machines in the VMware GSX
Server Administration Guide.
Physical (Raw) Disk
A physical disk directly accesses an existing local disk or partition. You can use physical
disks if you want GSX Server to run one or more guest operating systems from existing
disk partitions. Physical disks may be set up on both IDE and SCSI devices. At this time,
however, booting from an operating system already set up on an existing SCSI disk or
partition is not supported.