HP-UX vPars and Integrity VM V6.3 Administrator Guide

6 Storage devices
This chapter describes vPar and Integrity VM storage and explains how to configure and use vPar
and Integrity VM guest storage. The way you configure and manage vPar and VM guest storage
affects the way vPar and VM guest perform. To benefit most, learn how the VSP makes storage
available to vPars and VM guests.
6.1 Storage goals
To successfully configure and manage virtual storage, it is helpful to understand the basic goals
of the vPars and Integrity VM storage subsystem, including:
• Storage utilization
• Storage availability
• Storage performance
• Storage security
• Storage configurability
6.1.1 Storage utilization
The main purpose of vPars and Integrity VM is to increase system resource utilization on Integrity
servers. The vPar and VM guest storage subsystem meets this goal by permitting multiple vPars
and VMs to share a variety of physical storage adapters and devices that are available on an
Integrity server. Furthermore, the vPars and Integrity VM storage subsystem allows a single storage
LUN on the VSP to be carved up into smaller entities that can be used as separate individual disks
or DVDs on the virtual platform.
6.1.2 Storage availability
Like HP Integrity servers, it is expected that VMs and vPars have different storage device types
available for use. The vPar and VM guest storage subsystem allows a guest OS to use disks, DVDs,
tapes, and media changers. Additionally, the way that virtualization abstracts the physical hardware
provides a common supportable interface with which a guest OS can interact. Because a guest
OS accesses only vPars and Integrity VM virtual hardware, it can use physical hardware that it
does not support on an Integrity server.
6.1.3 Storage performance
Each release of the vPar and Integrity VM product strives to improve performance. Performance is
improved in each release by lowering costs of virtualization, exploiting new features in the VSP,
and tuning operating systems for the virtual platform. At the same time, vPars and Integrity VM
provides more virtualization choices to VSP administrators, so that they can find the best balance
between virtualization and performance to meet their needs.
6.1.4 Storage security
To ensure that multiple vPars and VMs can run on one physical machine without each accessing
the resources that belong to the others, the VSP isolates each VM and vPar. Using vPar and Integrity
VM commands, the VSP administrator determines the physical storage resources that each VM
and vPar can access. This storage isolation is maintained by the vPar and VM guest storage
subsystem through DMA boundary checks on each vPar/VM I/O operation, thereby ensuring that
one VM or vPar does not access the memory of another.
6.1 Storage goals 63