Sunday, February 16, 2014

Virtualization


VIRTUALIZATION


Its very useful concept in context of cloud systems. Virtualization means something which isn’t real, but gives all the facilities of a real. It is the software implementation of a computer which will execute different programs like a real machine.Virtualization is related to cloud, because using virtualization an end user can use different services of a cloud. The remote data center will provide different services in a full or partial virtualized manner.
Two types of virtualization are found in case of clouds:
  • Full virtualization
  • Para virtualization 
  1. Full Virtualization: In case of full virtualization a complete installation of one machine is done on another machine. It will result in a virtual machine which will have all the software that is present in the actual server. 
Figure 1 Full Virtualization
 
Here the remote data center delivers the services in a fully virtualized manner. Full virtualization has been successful for several purposes:
  • Sharing a computer system among multiple users
  • Isolating users from each other and from the control program
  • Emulating hardware on another machine 

      2. Para Virtualization: In Para virtualization, the hardware allows multiple operating systems to run on single machine by efficient use of system resources such as memory and processor. e.g. VMWare software. Here all the services are not fully available, rather the services are provided partially. Para virtualization has the following advantages:
  • Disaster recovery: In the event of a system failure, guest instances are moved to hardware until the machine is repaired or replaced.
  • Migration: As the hardware can be replaced easily, hence migrating or moving the different parts of a new machine is faster and easier.
  • Capacity management: In a virtualized environment, it is easier and faster to add more hard drive capacity and processing power. As the system parts or hardware can be moved or replaced or repaired easily, capacity management is simple and easier.
Figure 2 Para Virtualization