Virtualization Benefits:
Better resource utilization
Solution to space
Power consumption is less
Better security
Develop and test made easy
Run multiple OS on the same hardware
Manage outages
Easy upgrades to OS and applications
Administration made easy

Types of Virtualization

Hardware Virtualization
Application Virtualization
Memory virtualization
Storage Virtualization

Memory virtualization
It allows networked servers to share a pool of memory to improve software performance.
The memory pool can be accessed at the application level (through API) or operating system level (page cache)

Storage Virtualization
The physical storage resources are aggregated into storage pools, from which the logical storage is created. More storage systems can be added as and when needed at any time any place

Hardware virtualization
Running many OS above a physical hardware using hypervisors which emulates and share the hardware resources.

Application virtualization
Turn physical applications into virtual applications that are never installed but can seamlessly communicate with the local operating system, middleware, plug-ins, and other applications

We need Application Virtualization when two incompatibilities applications installed on the same instance of an OS. This technology isolates applications from the underlying operating system and from other applications to increase compatibility and manageability. The application never knows that it’s accessing a virtual resource instead of a physical one.

How Application virtualization works?
It works by replacing the some part of the runtime environment provided by the operating system. The layer intercepts all file and Registry operations into a single file and transparently redirects them to a virtualized location.

Since the application is working with one file instead of many files and registry entries spread throughout the system, it becomes easy to run the application on a different computer and previously incompatible applications can be run side-by-side.

The user machine need not have any application installed. Whenever they need to access the file associated with the application, they can connect to the application virtualizing server. The server then will push the application to the client system and the user can access read/edit the file from that application.

Content Redirection

Client-Server: The client application open all the files of the associated type encountered locally with the applications published on the server

Server-Client: Embedded URLs are intercepted on the server and sent to the client using the virtual channel. The locally installed browser will run the URL.

Advantages

Streams applications on demand over the Internet or via the corporate network to all clients.
Automates and simplifies application interoperability testing.
Application upgrades, patching made easy and no end-user involvement required.
No reboots, no waiting for applications to install, and no need to uninstall when retiring applications.
Enables controlled application usage to users.