By running as individual computers with individual operating systems and applications, virtual machines have the advantage of remaining independent of each other and of the physical host computer. The hypervisor allows you to run different operating systems on virtual machines at the same time.

The only difference between a virtual machine and a real one is that the real one does have real hardware, while the virtual machine emulates all its components. This makes it easy that, once the virtual machine is created, you can copy or move it to another computer, even if it has completely different hardware.

RAID (“Redundant Array of Inexpensive Disks” or “Redundant Array of Independent Disks”) is a data storage virtualization technology that combines multiple physical disk drive components into one or more logical drives for the purpose of data redundancy, performance enhancement or both. This was in contrast to the earlier concept of highly reliable mainframe disk drives called “big, expensive single disk” (SLED). Data is spread across the drives in one of several ways, called RAID levels, depending on the required level of redundancy and performance. Different schemes, or data striping layouts, are named with the word “RAID” followed by a number, for example, RAID 0 or RAID 1. Each scheme, or RAID level, provides a different balance between key objectives: reliability, availability, performance and capacity. RAID levels greater than RAID 0 provide protection against unrecoverable sector read errors as well as complete physical drive failures.

A VPN connection establishes a secure connection between you and the Internet. Through the VPN, all your data traffic is routed through an encrypted virtual tunnel. This disguises your IP address when you use the Internet, making your location invisible to everyone. A VPN connection is also secure against external attacks. This is because only you can access the data in the encrypted tunnel, and no one else can because you don’t have the key.

Many IT organizations deploy servers that are only running at a fraction of their capacity, often because they are dedicating their physical server to a specific application. This is often an inefficient mechanism because there is excess capacity that is not being consumed, leading to higher IT and operational costs. In an effort to drive higher capacity utilization and lower costs, virtualization was created.