Nutanix Glossary

What is Virtualisation?

October 26, 2022 | min

Virtualisation creates a virtual version of a once-physical item. In a datacentre, the most commonly virtualised items include operating systems, servers, storage devices, or desktops. With virtualisation, technologies like applications and operating systems are abstracted away from the hardware or software beneath them. Hardware virtualisation involves virtual machines (VMs), which take the place of a “real” computer with a “real” operating system.

What are Virtual Machines?

Virtual machines are an emulation of a computer system. The underlying hardware is copied by a hypervisor to run multiple operating systems. While VMs have been around for 50 years, they are now becoming more popular with the advance of the remote workforce and end-user computing. Some popular virtualisation stacks and hypervisors include VMware vSphere with ESXi, Microsoft Windows Server 2016 with Hyper-V, Nutanix AHV Virtualisation, Citrix XenServer, and Oracle VM.

What is a Hypervisor?

A hypervisor is a software that abstracts and isolates hardware and operating systems into virtual machines with their own memory, storage, CPU power, and network bandwidth. Another key function of hypervisors is isolating the VMs from one another and handles communications between all the VMs.

A hypervisor is composed of three parts that work together to model the hardware:

  • Dispatcher: Tells the VM what to do

  • Allocator: allocates system resources

  • Interpreter: instructions that are executed

How Does Virtualisation Work?

One of the main reasons businesses use virtualisation technology is server virtualisation, which uses a hypervisor to “duplicate” the hardware underneath. In a non-virtualised environment, the guest operating system (OS) normally works in conjunction with the hardware. When virtualised, the OS still runs as if it's on hardware, letting companies enjoy much of the same performance they expect without hardware. Though the hardware performance vs. virtualised performance isn’t always equal, virtualisation still works and is preferable since most guest operating systems don’t need complete access to hardware.

As a result, businesses can enjoy better flexibility and control and eliminate any dependency on a single piece of hardware. Because of its success with server virtualisation, virtualisation has spread to other areas of the datacentre, including applications, networks, data, and desktops.

Benefits of Virtualisation

There are many benefits of virtualisation in computing. Put simply, virtualisation solutions streamline your enterprise datacentre. It abstracts away the complexity in deploying and administering a virtualised solution, while providing the flexibility needed in the modern datacentre.

Not to mention, virtualisation can help create a “greener” IT environment by reducing costs on power, cooling, and hardware. But cost savings aren’t the only advantage of opting for virtualised solutions. Here are more reasons organisations are going virtual:

  • Minimise Servers - Virtualisation minimises the amount of servers an organisation needs, letting them cut down on heat buildup associated with a server-heavy datacentre. The less physical “clutter” your datacentre has, the less money and research you need to funnel into heat dissipation. 

  • Reduce Hardware - When it comes to saving money, minimising hardware is key. With virtualisation, organisations are able to reduce their hardware usage, and most importantly, reduce maintenance, downtime, and electricity overtime. 

  • Quick Redeployments - Virtualisation makes redeploying a new server simple and quick. Should a server die, virtual machine snapshots can come to the rescue within minutes.

  • Simpler Backups - Backups are far simpler with virtualisation. Your virtual machine can perform backups and take snapshots throughout the day, so you always have the most current data available. Plus, you can move your VMs between servers, and they can be redeployed quicker.

  • Reduce Costs & Carbon Footprint - As you virtualise more of your datacentre, you’re inevitably reducing your datacentre footprint—and your carbon footprint as a whole. On top of supporting the planet, reducing your datacentre footprint also cuts down dramatically on hardware, power, and cooling costs.

  • Better Testing - You’re better equipped to test and re-test in a virtualised environment than a hardware-driven one. Because VMs keep snapshots, you can revert to a previous one should you make an error during testing.

  • Run Any Machine on Any Hardware - Virtualisation provides an abstraction layer between software and hardware. In other words, VMs are hardware-agnostic, so you can run any machine on any hardware. As a result, you don’t have the tie-down associated with vendor lock-in.

  • Effective Disaster Recovery - When your datacentre relies on virtual instances, disaster recovery is far less painful, and you end up facing much shorter, infrequent downtime. You can use recent snapshots to get your VMs up and running, or you may choose to move those machines elsewhere.

  • Cloudify Your Datacentre - Virtualisation can help you “cloudify” your datacentre. A fully or mostly virtualised environment mimics that of the cloud, getting you set up for the switch to cloud. In addition, you can choose to deploy your VMs in the cloud.

Types of Virtualisation

Data virtualisation

Data virtualisation is a type of data management that integrates data from multiple applications and physical locations for use without the need for data replication or movement. It creates a single, virtual abstract layer that connects to different databases for virtual views of the data.

Server virtualisation

Server virtualisation is creating multiple instances of one server. These instances represent one virtual environment. Within each virtual environment is a separate operating system that can run on their own. This allows one operating machine to do the work of many machines, eliminating the need for data sprawl and saves on operating expenses.

Operating system virtualisation

Operating system virtualisation is similar to server virtualisation. The host operating system is reconfigured to operate multiple isolated operating systems such as Linux and Windows on one machine that allows multiple users to work from it in different applications at the same time. This is also known as operating system-level virtualisation.

Desktop virtualisation

Desktop virtualisation is a type of software that separates the main desktop environment from other devices that use it. This saves time and IT resources as one desktop environment is deployed onto many machines at once. This also makes it easier to deploy updates, fix systems and add security protocols across virtual desktops at once.

Network virtualisation

Network virtualisation combines network hardware and software functionality into a single entity. Often combined with resource virtualisation, it combines multiple resources that are then split up into separate segments and assigned to the devices or servers that need them. This type of virtualisation improves network speed, scalability, and reliability.

Storage virtualisation

Storage virtualisation is taking storage resources from multiple smaller devices and combining them into one large storage device. Administrators can use this storage as needed through a single, central console via virtual machines and physical servers. To do this, the software takes storage requests and determines which device has the capacity to use it as needed.

The Evolution of Virtualisation

Decades ago, operating system (OS) virtualisation technology was born. In this form, software is used to let hardware run multiple operating systems simultaneously. Started on mainframes, this technology enabled IT administrators to avoid spending too much costly processing power.

Beginning in the 1960s, virtualisation and virtual machines (VMs) started on just a couple of mainframes, which were large, clunky pieces with time-sharing capabilities. Most notable among these machines was IBM 360/67, which became a staple in the world of mainframes in the 1970s. It wasn’t long before VMs entered the heart of personal computers in the 1980s.

But mainstream virtualisation adoption didn’t begin until the late ‘80s and early ‘90s. While some VMs like those on IBM’s mainframes are still used today, they’re not nearly as popular, and few companies regard mainframes as a business staple. The first business to make VMs mainstream was Insignia Solutions, who created a SoftPC, an x86-based software emulator. This success inspired more organisations—namely Apple, Nutanix, and later, Citrix—to come out with their own virtualisation products.

Why Should Organisations Opt for Virtualisation?

Organisations hoping to pursue a more cloud-like IT environment will need to set their sights on virtualisation first. Virtualising your datacentre helps you use your server resources far more efficiently. In the past, businesses would have to dedicate one application—such as email—on a single server. In those cases, businesses would either over-accumulate multiple servers to take on their multiple applications, or they’d face a different issue altogether: Resources being underused on an entire server.

Either way, this method is costly, space-consuming, and inefficient. Thanks to virtual solutions, IT teams can run multiple applications, workloads, and operating systems on just a single virtual machine, and resources can be added and removed as needed. Virtualisation scales easily with businesses. As demands rise and fall, it helps organisations stay on top of their resource utilization and respond faster as changes arise.

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