HP-UX vPars and Integrity VM V6.3 Administrator Guide
1.4.2 Overview of Integrity VM
Integrity VM instances are abstractions of real physical machines. The guest operating system runs
on the VM as it would run on a physical Integrity server, with minimal modifications. The environment
of the VM is virtualized and managed by the Virtual Machine Monitor (VMM) sub-system that
resides on the VSP. Each VM runs an instance of HP-UX (OpenVMS operating system is not
supported). Applications running within a VM guest run the same as when run on HP-UX natively.
The VM is allocated Virtual CPUs and virtualized memory. The virtual CPUs run a fraction of time
on the physical CPU, depending on the percentage of entitlement that is configured for the virtual
CPUs and on number of virtual CPUs from other guests sharing the physical CPU and also on the
current CPU usage on all the virtual CPUs. Figure 2 (page 19) shows an Integrity VM instance on
the left side. The virtual CPU is shown mapped to a physical CPU on the VSP. For more information
about virtual CPU entitlements, see Section 9.1.4 (page 135).
Each VM guest requires a minimum of one virtual CPU, one network port, one root disk, memory
sufficient for HP-UX, and the hosted applications. The network and storage I/O is through AVIO.
Direct IO is also supported on Integrity VMs.
HP-UX 11i v2 and HP-UX 11i v3 are supported as guest operating systems on Integrity VM. There
are no set limit to the number of VMs that can be configured, but not more than 254 VMs can be
booted simultaneously on a single VSP. For more information about VM attributes, see Section 9.1
(page 133).
1.4.3 Overview of vPars
Virtual Partition is an instance of an HP-UX 11i v3 operating system having its own dedicated
physical cores and dedicated memory. Each instance of HP-UX running in a partition is isolated
from all other instances providing application and operating system fault isolation. Applications
running on top of HP-UX using vPars run the same as when run on HP-UX native-mode (standalone).
Each vPar requires a minimum of one dedicated processor core (CPU), one network port, one root
disk, and memory sufficient for HP-UX and the hosted applications. The storage and network I/O
is in shared-mode inside the vPar. There are virtual NIC and virtual HBA that are configured and
mapped to the AVIO sub-systems on the VSP. The VSP and vPars have a thin communication layer
to exchange control information and messages between them. This ensures that vPars can provide
near-native performance and provide minimum virtualization overhead to the hosted applications.
Direct IO is also supported on vPars.
For more information about configuration limits, see Section 9.1.8 (page 137).
1.4.4 Types of I/O
The vPars and Integrity VM supports two types of I/O device – AVIO and DIO. AVIO was introduced
with Integrity VM Version 3.5 in December 2007 and since then it has been supported with all
further releases of HPVM and vPars and Integrity VM product. AVIO is supported for both storage
and networking devices and is available for both HP-UX 11i v2 and HP-UX 11i v3 guests. With
HPVM Version 4.2.5, it was also introduced for OpenVMS guests, but, vPars and Integrity VM 6.x
does not support OpenVMS guests.
The AVIO feature uses a new storage and networking AVIO guest driver for use within the guests
and corresponding AVIO host drivers for use on the HPUX host. The guest drivers are para-virtualized
there by eliminating some of the virtualization overhead, and together with the host driver they
deliver a streamlined and re-architected I/O path for both storage and networking in improved
performance for I/O intensive workloads. For a technical overview on the AVIO feature, see HP
Integrity VM Accelerated Virtual I/O Overview white paper at http://www.hp.com/go/
hpux-hpvm-docs.
With DIO, vPars and Integrity VM guests can have direct control of a I/O device and is supported
only with networking devices. The DIO networking feature minimizes the device emulation overhead
and also allows guest operating system to control devices for which emulation does not exist, thus
20 Introduction