but need more time to understand virtualization on HP-UX ..
http://en.wikipedia.org/wiki/Virtualization
http://www.kernelthread.com/publications/virtualization/
Why Virtualization: A List of Reasons
Following are some (possibly overlapping) representative reasons for and benefits of virtualization
Virtual machines can be used to
consolidate the workloads of several under-utilized servers to fewer
machines, perhaps a single machine (server consolidation). Related
benefits (perceived or real, but often cited by vendors) are savings
on hardware, environmental costs, management, and administration of
the server infrastructure.
The need to run legacy
applications is served well by virtual machines. A legacy
application might simply not run on newer hardware and/or operating
systems. Even if it does, if may under-utilize the server, so as
above, it makes sense to consolidate several applications. This may
be difficult without virtualization as such applications are usually
not written to co-exist within a single execution environment
(consider applications with hard-coded System V IPC keys, as a
trivial example).
Virtual machines can be used to
provide secure, isolated sandboxes for running untrusted
applications. You could even create such an execution environment
dynamically - on the fly - as you download something from the
Internet and run it. You can think of creative schemes, such as
those involving address obfuscation. Virtualization is an important
concept in building secure computing platforms.
Virtual machines can be used to
create operating systems, or execution environments with resource
limits, and given the right schedulers, resource guarantees.
Partitioning usually goes hand-in-hand with quality of service in
the creation of QoS-enabled operating systems.
Virtual machines can provide the
illusion of hardware, or hardware configuration that you do not have
(such as SCSI devices, multiple processors, ...) Virtualization can
also be used to simulate networks of independent computers.
Virtual machines can be used to
run multiple operating systems simultaneously: different versions,
or even entirely different systems, which can be on hot standby.
Some such systems may be hard or impossible to run on newer real
hardware.
Virtual machines allow for
powerful debugging and performance monitoring. You can put such
tools in the virtual machine monitor, for example. Operating systems
can be debugged without losing productivity, or setting up more
complicated debugging scenarios.
Virtual machines can isolate what
they run, so they provide fault and error containment. You can
inject faults proactively into software to study its subsequent
behavior.
Virtual machines make software
easier to migrate, thus aiding application and system mobility.
You can treat application suites
as appliances by "packaging" and running each in a virtual
machine.
Virtual machines are great tools
for research and academic experiments. Since they provide isolation,
they are safer to work with. They encapsulate the entire state of a
running system: you can save the state, examine it, modify it,
reload it, and so on. The state also provides an abstraction of the
workload being run.
Virtualization can enable existing
operating systems to run on shared memory multiprocessors.
Virtual machines can be used to
create arbitrary test scenarios, and can lead to some very
imaginative, effective quality assurance.
Virtualization can be used to
retrofit new features in existing operating systems without "too
much" work.
Virtualization can make tasks such
as system migration, backup, and recovery easier and more
manageable.
Virtualization can be an effective
means of providing binary compatibility.
Virtualization on commodity
hardware has been popular in co-located hosting. Many of the above
benefits make such hosting secure, cost-effective, and appealing in
general.
Virtualization is fun.
source : http://www.kernelthread.com/publications/virtualization/
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