Server Virtualization
What is Virtualization..?
Virtualization is a technique of partitioning or dividing the resources of a single
server into multiple segregated execution environments. Each of these environments
runs independently of the other, thus allowing multiple operating systems to run on
the same hardware. This concept has been widely used in the world of mainframe
computers over the years.
What is VMM (Virtual Machine Monitor)?
Each execution environment is called a guest and the server on
which they execute is called the host. The software running on the host that acts as
a bridge between the host and the guests, and that enables these multiple execution
environments is commonly referred to as the Virtual Machine Monitor (VMM) or
a Hypervisor.
What are the Methods in Virtualization Technique ?
System emulation: The execution environment is called a virtual machine and
it emulates all the hardware resources. This emulation layer in turn uses the
real hardware resources from the host.
This approach Followed by : VMware, Microsoft virtual PC
Paravirtualization: There is no hardware emulation. The operating system
that runs on a guest needs to be a modifed version that is aware of the
fact that it is running inside a hypervisor.
This approach Followed by : Xen
Operating System level virtualization: Each guest instance is isolated and
runs in a secure environment. However, you can execute only multiple
instances of guests that run the same operating system as the host.
This approach Followed by : Sun Solaris
What is Xen?
Xen is an open-source paravirtualization technology that provides a platform for
running multiple operating systems in parallel on one physical hardware resource,
while providing close to native performance. Xen supports several operating
systems—Linux, FreeBSD and NetBSD. The current version of Xen also supports
the new generation of AMD Pacifca and Intel VT-x chipsets and can run an OS on
these chips without any modifcations by using a version of the hypervisor called
the Hardware Virtual Machine (HVM)
What is HVM (Hardware Virtual Machine) ?
HVM mediates between the guest operating
system and the hardware and passes on the calls made by the guest to the physical
hardware.
Xen Architecture
Intel Server Virtualization Demo:
Intel® Xeon® processors based on Intel® Core™ microarchitecture integrate hardware for virtualization into all key server components including Intel® Virtualization Technology (Intel® VT) helping IT organizations consolidate more applications and heavier workloads on each server to improve flexibility, reliability, and total cost of ownership (TCO).
Intel® Virtualization Technology for servers Demo :
Flexible virtualization
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