Specifications

CHAPTER 6 Using Disks in a Virtual Machine
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For example, if your SCSI drive has SCSI ID 2, select SCSI 0:2. If you do not know
the SCSI ID set on your physical SCSI drive, try using SCSI 0:0.
On the advanced settings screen, you can also specify a disk mode. This is useful
in certain special-purpose configurations in which you want to exclude disks
from the snapshot. For more information on the snapshot feature, see Taking
Snapshots on page 153.
Normal disks are included in the snapshot. In most cases, this is the setting you
want.
Independent disks are not included in the snapshot. You have the following
options for an independent disk:
• Persistent — changes are immediately and permanently written to the disk.
• Nonpersistent — changes to the disk are discarded when you power off or
revert to the snapshot.
When you have set the filename and location you want to use and have made
any selections you want to make on the advanced settings screen, click Finish.
6. Begin using your virtual machine.
Known Issues and Background Information on Using SCSI Physical Disks
Some known issues with SCSI physical disks involve disk geometry, appropriate drivers
and operating system configuration.
Geometry
In some cases, it is not possible to boot a raw SCSI drive inside a virtual machine
because the SCSI adapter in the physical computer and the BusLogic adapter in the
virtual machine describe the drive in different ways. The virtual machine might hang
during the boot, GSX Server might crash or GSX Server might fail with an ASSERT or
other error message.
This problem is most likely to affect smaller drives — less than 2GB.
In order to share the same BIOS interface used by IDE disks (which is required in order
to boot), all SCSI disks need to have a geometry, which is a fabricated value for the
number of cylinders, sectors and heads on the disk.
In fact, a SCSI disk appears to a computer as a single flat entity from sector 1 up to the
highest sector on the disk. As a result, every SCSI vendor has its own approach to
taking the capacity of a SCSI disk and generating a geometry to use for booting.
The conversion from a given geometry to an absolute sector number depends on the
geometry. If you have a disk with a boot sector written by a program running on the