Application Notes Usage and best practices for Device Mapper Multipath with Xen enabled virtual machines for HP StorageWorks Disk Arrays (5697-7828, April 2009)

Xen overview
Figure 1 Xen architecture
Domain0
Domain0 (Dom0) is the operating system installed on the physical hardware which provides host
environment to the virtual machine. It is a special privileged domain, used to manage virtual machines.
It provides the administrator a graphical and command line environment to manage the virtual
machines. The xen daemon monitors the configuration information about the virtual machines and
controls their operations.
DomainU
DomainU (DomU) is Xen aware, modified operating system created on Dom0. Xen supports various
operating systems as DomU. Applications on the DomU interact with the hardware through Dom0,
which provides virtual block device and virtual network device drivers also known as backend interface
to DomU instances. Within each DomU there are some lightweight device drivers to access virtual
block devices and virtual network devices which are called frontend drivers.
Installing virtual machine (DomU)
This section addrsses the following topics:
• Prerequisites
• Installing instructions
• Preparing disks for DomU
• Storage provisioning for virtual machine
• iSCSI devices on virtual machines
Prerequisites
Following are the prerequisites to install virtual machines:
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