A guide to server virtualisation
Server virtualisation has been essential in the creation of virtual servers such as VPS hosting and creating Bare Metal Servers. By allowing one physical server to be split into several other virtual servers, the server game has been changed forever.
This guide will explore what server virtualisation is, the history of virtualisation, benefits, use cases and whether you could outsource or self-manage your server.
What is server virtualisation?
Server virtualisation is the process by which a single physical server is divided into multiple virtual instances, usually achieved via a software application. For example, if you’re using VPS hosting, then the virtual private server where your project is hosted was created by server virtualisation.
Server virtualisation is also used as a way of masking server resources. This means users don’t have access to sensitive information like the different operating systems at play, how many processors there are, or even the number of physical servers.
How does server virtualisation work?
Isolating a server’s physical hardware is done by a hypervisor – which is a type of software used specifically for creating and running VMs. This hypervisor sits between the server and the new virtual machine, and it virtualises all of the pre-existing physical resources to be used on multiple different VMs. These new virtual servers can then be passed onto anyone who needs them.
Why server virtualisation?
Sharing a similar history with hypervisors, it’s worth noting that virtualisation is not a new concept. Server virtualisation was developed initially by IBM in the 1960s to address the inefficiency of using multiple physical servers, where each server was often underused.
Virtualisation allowed IBM to share their powerful resources and run multiple tasks at the same time, in order to maximise the efficiency of their mainframes. Then, in the 80s, the rise of x86 computing made affordable and simple computers widely available. We saw companies shift from mainframes to individual computers to run each application for an increasing number of users. However, these x86 computers were limited in their processing power, memory, and storage, which meant they could usually only handle one application at a time. The shift from one large computer to many smaller ones made virtualisation highly inefficient.
By the early 2000s, enterprise servers often had multiple processors and much more memory and storage than most applications needed, leading to wasted resources and capital. This is when software called hypervisors came about, which made it easier to create virtual machines (VMs) that simulate a complete computer system. This allowed individuals (but mostly businesses) to use the full potential of their servers by running multiple operating systems and applications on a single physical server, just like those original mainframes – but much more efficiently.
Types of server virtualisation
Before we get into the benefits, let’s take a look at the main types of server virtualisation out there. There are three different techniques for server virtualisation, but they all involve the division of a physical server (AKA the “host”) into virtual ones, which are often called “guests”.
1. Full virtualisation
Full virtualisation – sometimes called “VM model” virtualisation – uses a type of software called a hypervisor. The hypervisor communicates directly with the host server’s CPU, ensuring that the virtual servers stay secure and independent from one another. Every guest on the host server has its own operating system – you can even run Linux and Windows on neighbouring virtual servers, and they’ll have no knowledge of each other. The other core function of the hypervisor is transferring the right type of resources from the physical server to the virtual ones, in line with their needs.
One slight snag with full virtualisation is that the hypervisor itself uses resources, which can potentially hamper speed and performance.
2. Para-virtualisation
While para-virtualisation also relies on a hypervisor, the actual process is a little different. The operating systems on the guest servers are all aware of each other, so the hypervisor doesn’t need as much power, as it isn’t necessary to keep the servers completely in the dark.
3. OS-level virtualisation
By contrast, there’s no hypervisor involved with OS-level virtualisation. Instead, the OS on the host server carries out the same function as the hypervisor, but this does mean that the guest servers are required to run on the same operating system in order to work. Plus, if something happens to corrupt the host’s OS, all the virtual servers could be compromised too.
What are the benefits of server virtualisation?
From increased efficiency to reduced costs, there are a lot of advantages to server virtualisation. Here are some of the biggest benefits you can expect:
1. Server consolidation
With server virtualisation, one physical server can become much more efficient, using far more of its processing power by hosting a handful of virtual guest servers. This also reduces the number of physical ones needed in an enterprise.
2. Versatility
Server virtualisation also makes most physical servers more versatile in terms of use cases – especially if they’re segmented via full or para-virtualisation. This is because each virtual machine (VM) has its own OS running, so you could deploy Linux, Windows and any other operating systems on a single host server.
3. Reduced operating costs
With fewer physical servers up and running, the hosting provider’s operating costs are bound to go down. Server consolidation should mean your data centres are using less power, making them cheaper to run, and also saving you money on actual server hardware too.
4. Affordable web hosting
This technology also provides a more affordable web hosting solution, as customers are able to rent a VPS, which is considerably cheaper than hiring a whole physical server for your project.
5. Better disaster recovery
It’s also easier to manage a virtual server if the worst happens and something goes wrong with your hardware. For example, you can migrate a VM directly over onto another physical server to keep all the data safe, without losing access.
Uses of server virtualisation
Server virtualisation has a number of key use cases that make it a cornerstone of both VPS and cloud server technology.
1. Support for multiple operating systems
As we mentioned before, one of the biggest advantages of server virtualisation is that it can support multiple platforms on a single server. This gives organisations the flexibility to run Windows right alongside Linux, or any other operating systems they need to make use of.
2. Practising redundancy
A redundant server is effectively a duplicate. Historically, redundancy referred to another physical server running the same application as your primary one, so it could be used in the event of a hardware failure. With server virtualisation, you can practise redundancy without buying additional physical servers, using a neighbouring virtual one instead.
3. Testing and development
This technology also gives developers the flexibility to run tests without affecting the production environment. With a quick cloning process, they can create an identical VM, where they can safely experiment with changes and software updates in a test environment.
4. Improve availability
Virtualisation can help boost the reliability and availability of workloads in VMs. For example, live migration lets you move a VM between physical servers without disrupting the workload.
Plus, any critical VMs (such as those that have important workloads) can be loaded first to minimise disruptions to your service. You can even configure your server(s) to save “snapshots” (make recent copies of VMs, protecting them and allowing for quick restarts with little data loss).
5. Remote working
It’s quite clear that remote working isn’t going anywhere. In fact, remote working has highlighted the importance of having a Virtual Desktop Infrastructure (VDI). VDI uses virtualisation technology to provide virtual desktops that users can reach from any location and device, making it an ideal option for businesses with remote teams or flexible work arrangements.
What’s great is that employees are not required to have powerful laptops or desktops at home. They simply connect to a virtual machine managed by you (or your IT department). This centralised approach enables you or IT to perform updates, install software, and maintain security without needing to access individual employees' computers.
Self-managed or outsourced virtualisation?
We do cover self-managed and outsourced virtualisation in a dedicated guide – however, it’s worth noting here as it’s something you’ll need to consider depending on your available (or unavailable) resources.
Ask yourself whether you’re able to manage server virtualisation yourself or need to outsource the help. You’ll need to think about money, control, and how you'll handle technical tasks. If you do it yourself, you'll have more say over how your servers are set up and you can change how resources are used right away.
If you outsource, you don't have to worry about the hardware and you get perks like AI that balances the workload. This can save you money and work if you don't have the setup or know-how to manage servers in-house. Both choices have their good points, depending on what your business needs and can do.
What’s the difference between server virtualisation and network virtualisation?
There’s often some confusion between server and network virtualisation, but the basic principle is the same. As we’ve established, server virtualisation lets you create several virtual machines on one physical server.
Network virtualisation separates the physical network into multiple virtual networks within the same infrastructure. These virtual networks can establish their own unique topologies, traffic regulations, and settings, similar to having distinct physical networks (without needing extra hardware).
Now you know more about server virtualisation
It’s virtualisation technology that makes our VPS Hosting possible – and this is one of the most popular web hosting options on the market, particularly for SMBs who have outgrown shared hosting plans, but don’t have the budget for a dedicated server.
Head over to our blog to find out more about the benefits of VPS hosting, or talk to our sales team if you’re still unsure about which type of server is most suited to your project.