Installation guide

C H A P T E R 2 Creating and Configuring Virtual Machines
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unless they detect a discrete failure to access a primary disk. Reporting that a targeted
disk is busy, rather than unavailable, may cause mirroring programs to repeat the
connection attempt instead of selecting a duplicate disk.
ESX Server does not automatically include an explicit
returnBusyOnNoConnectStatus option definition for each SCSI disk in a
virtual machine. If the option is not defined for a disk in the virtual machine
configuration file, ESX Server defaults to a value of TRUE. You need to both create an
option definition for each disk and set it to FALSE if you wish to override the default
value of TRUE. See Modifying the Configuration File Directly (Advanced Users Only)
on page 141 for instructions.
Modifying the SMBIOS UUID
Each ESX Server virtual machine is automatically assigned a universally unique
identifier (UUID), which is stored in the SMBIOS system information descriptor. It can
be accessed by standard SMBIOS scanning software — for example SiSoftware Sandra
or the IBM utility smbios2 — and used for systems management in the same ways
you use the UUID of a physical computer.
The UUID is a 128-bit integer. The 16 bytes of this value are separated by spaces
except for a dash between the eighth and ninth hexadecimal pairs. So a sample UUID
might look like this:
00 11 22 33 44 55 66 77-88 99 aa bb cc dd ee ff
Generating the UUID Automatically
The automatically generated UUID is based on the physical computer’s identifier and
the path to the virtual machine’s configuration file. This UUID is generated when you
power on or reset the virtual machine. The UUID that is generated remains the same
so long as the virtual machine is not moved or copied.
The automatically generated UUID is also written to the virtual machine’s
configuration file as the value of uuid.location.
If you move or copy the virtual machine, a new UUID is generated when the virtual
machine is powered on — based on the physical computer’s identifier and path to
the virtual machine’s configuration file in its new location.
If you suspend and resume a virtual machine, this does not trigger the process that
generates a UUID. Thus, the UUID in use at the time the virtual machine was
suspended remains in use when the virtual machine is resumed, even if it has been
copied or moved. However, the next time the virtual machine is rebooted, the UUID is
generated again. If the virtual machine has been copied or moved, the UUID is
changed.