virtualization

virtualization

1. running multiple operating systems and user applications on the same hardware.

2. benefits

   • server consolidation
   • easier development
   • cloud computing
   • increase IT
   • reduced capital
   • enable standardization

3. challenges

   • resource distribution
   • VM Sprawl
   • security
   • backward compatibilty
   • backup
   • licensing issues

4. drawbacks

   • high cost of implementation
   • security risk
   • availability issue
   • scalability issue
   • time taking process

5. hypervisors

   • hosted
     • runs as a software layer
     • VM Workstation, Mircosoft Virtual PC
   • bare metal
     • runs directly on the host's hardware
     • VMware ESX, Microsoft Hyper-V

6. Full virtualization

   • Virtual Machine Monitor (VMM) runs in the privileged Ring 0
   • VMM decouples guest operating system (OS) from the underlying physical hardware
   • Guest OS is not aware of being virtualized

7. para virtualization

   • Guest operating system (OS) knows that it is virtualized
   • Guest operating system (OS) knows that it is virtualized
   • Modified guest OS kernel is used, such as Linux and OpenBSD