Specifications

CHAPTER 6 Using Disks in a Virtual Machine
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unaware of the other, data corruption may occur if both operating systems read
or write to the same partition. It is critical that the virtual machine not be allowed
to modify any partition mounted under the Linux host or in use by another
virtual machine. To safeguard against this problem, be sure the partition you use
for the virtual machine is not mounted under the Linux host.
5. Set the device group membership or device ownership. The master physical disk
devices must be readable and writable by the user who runs GSX Server. On
most distributions, the raw devices (such as /dev/hda and /dev/hdb)
belong to group ID disk. If this is the case, you can add GSX Server users to the
disk group. Another option is to change the owner of the device. Please think
carefully about security issues when you explore different options here.
It is typically a good idea to grant GSX Server users access to all
/dev/hd[abcd] raw devices that contain operating systems or boot
managers and then rely on GSX Server’s physical disk configuration files to guard
access. This provides boot managers access to configuration and other files they
may need to boot the operating systems. For example, LILO needs to read
/boot on a Linux partition to boot a non-Linux operating system that may be
on another drive.
6. If you plan to run a second Linux installation from an existing partition as a guest
operating system, and your physical machine’s /etc/lilo.conf has a
memory register statement such as Append= "mem…", you may want to
adjust the append memory parameter or create a new entry in LILO for running
Linux in a virtual machine.
Many newer Linux distributions recognize all physical memory in the physical
machine, whereas many older Linux distributions see only the first 64MB of
memory by default. Machines with more than 64MB of memory that run the
older distributions may have the Append= "mem=…" parameter added under
the Image=… section of lilo.conf to tell Linux to look for more memory
than seen by default.
If the amount of memory configured in lilo.conf exceeds the amount of
memory assigned to the virtual machine, the guest operating system is likely to
panic when the virtual machine tries to boot the second Linux installation.
You can create another entry in lilo.conf for running Linux in a virtual
machine by specifying a different amount of memory than what should
normally be recognized when Linux boots directly on the physical machine.