Storage Area Networks For Dummies®

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Par t V: Understanding the Cool Stuff
simultaneously in the same box. These hardware virtualization servers also
provide exotic connections such as Infiniband inside the box to ensure massive
scalability and fast performance. Many great whitepapers are available from the
hardware vendors on server virtualization.
VMware (owned by EMC) is the software-based virtualization solution with
all the buzz these days, but Microsoft and other software vendors like Virtual
Iron are not sitting still. The simple reason software-based server virtualization
solutions are taking off is the ability to turn a single physical server into
many virtual servers without having to buy the Big Iron hardware, so you
can save money on the hardware to run your applications. A software-based
virtual server solution runs on top of any Intel- or AMD-based computer with
enough memory.
Once a server is virtualized on top of the physical server, you can move the
virtual server between other physical servers by simply dragging the virtual
server to another machine (see Figure 15-7). The storage needs to be shared
in a SAN, or connected to an iSCSI storage resource. Forget about issues with
bringing down applications for hardware maintenance! Virtualization makes
maintenance a simple drag-and-drop process.
In summary, server virtualization software makes a single physical server
look like many individual servers by abstracting the hardware layer in the
server itself. Server virtualization hardware takes a single physical server and
stuffs dozens or even hundreds of CPUs in the box, along with powerful hardware
abstraction at the firmware level, to provide a robust platform for the
virtual servers themselves.
VM1
3
4
Virtual Infastructure
Figure 15-7:
Softwarebased
server virtualization.
Virtual server running on
physical server
Moving virtual servers between
physical servers