Servers before Virtualization

Before virtualization, there was a one-to-one relationship between a physical server and an operating system.

In that operating system, apps providing services such as a web server, email server, etc. would run.

One physical server would be used for the web server, one for the email server, one for the database server, etc.

This is inefficient for multiple reasons:

• Each physical server is expensive and takes up space, power, etc.

• The resources on each physical server (CPU, RAM, Storage, NIC) are typically under-used.