Hypervisor

A hypervisor is a program that would enable you to host several different virtual machines on a single hardware. Each one of these virtual machines or operating systems you have will be able to run its own programs, as it will appear that the system has the host hardware's processor, memory and resources.

In reality, however, it is actually the hypervisor that is allocating those resources to the virtual machines.

In effect, a hypervisor allows you to have several virtual machines all working optimally on a single piece of computer hardware. 

Now, hypervisors are fundamental components of any virtualization effort. You can think of it as the operating system for virtualized systems. It can access all physical devices residing on a server.

How does it work?

The servers would need to execute the hypervisor. The hypervisor, in turn, loads the client operating systems of the virtual machines.  The hypervisor allocates the correct CPU resources, memory, bandwidth and disk storage space for each virtual machine.

two types of hypervisors:

1. hosted hypervisors
2. native hypervisors

native hypervisors run directly on the hardware while a hosted hypervisor needs an operating system to do its work.

Microsoft Hyper-V hypervisor, VMware,Oracle VM Server are example of native Hypervisors.

Windows, Linux or FreeBSD, VirtualBox and VMWare Workstation are example of Host Hypervisors.

Native hypervisors are faster and more efficient as they do not need to go through the operating system and other layers that usually make hosted hypervisors slower.

Hosted hypervisors, on the other hand, are much easier to set up than Native hypervisors because you have an OS to work with. 

Hypervisors for Data Replication:

Hypervisors may be used in data services for easy cloning and replication.

 If you have a lot of virtual machines running on a particular hardware, you will have to get a significant amount of storage in order to be able to store the entire volume. With hypervisor-based replication, you can choose which VMs and what parts are to be replicated, so that you could save up on storage space.

 If you are currently using VMWare, you can get hypervisor-based replication in vSphere.

Cloud Computing Security

A hypervisor is a natural target for hackers because its designed control all the resources of the hardware while managing all the virtual machines residing on it.