Using virtual machines (VM) and virtual servers is no new task. We have been working with the concept of providing time-sharing solutions since the late 1960s and early 1970s. This was because the cost of using mainframe computers was extortionate and logically it made more economical sense to utilize time sharing.
With the release of massive data centers, the use of virtualization techniques has increased to make use of physical hardware. Physical servers can be bundled to create massive, aggregated pools of resources such as CPUs, memory, storage. Even aspects such as networking, and virtualization of applications are possible.
A virtual server replicates the same functionality as a physical server. However, multiple virtual servers can be applied to a pool of servers. Virtual servers may be applied against a bare metal computer which allows for its operating system and interfaces to integrate into the physical server’s resources.
There are many services today that allow for a physical to virtual (P2V) server migration to occur. These can range from simple and free, to quite expensive and feature rich.
A virtual server re-creates the functionality of a dedicated physical server. It exists transparently to users as a partitioned space inside a physical server. Virtual servers makes it easy to reallocate resources and adapt to dynamic workloads. Ultimately, a virtual server is meant to make the best use of the overall physical compute resources, thus providing a better return on investment for each organization.
Virtual server advantages
Virtual server disadvantages
There are a few different methods of providing a virtual server, these are known in the industry as type-1 and type-2. Type-1 is a native or bare-metal virtual server that runs directly on the host server’s hardware to control, manage the resources and the guest operating systems. Popular examples of this would be something like VMWare ESXi or Microsoft Hyper-V, and Oracle VM.
Type-2 is a hosted solution that runs on a conventional operating system, the same as other programs do. This means that the guest operating system runs on top of the host operating system. Examples of this are Parallels Desktop, VirtualBox, and VMWare Workstation.
This is outlined above as a type-1 method. This full virtualization will run directly on the machine’s physical hardware. There isn’t an underlying operating system. This provides the virtual server with direct access to the hardware without any other software getting in the way. Because of this, system administrators and IT professionals often find that this is the most efficient way of performing virtualization. The type-1 or full virtualization is how most enterprise organizations run their virtual servers.
Type-1 virtual servers are often more secure because the hypervisor that controls the virtualization runs directly on the physical hardware.
This is outlined above as the type-2 method. Type 2 is sometimes called a hosted hypervisor or an OS-level virtualization. This is because the overall virtual server relies on the existing host machine’s operating system to run. This has an impact on computer resources such as processing, memory, storage, and networking resources.
You’re unlikely to see a large enterprise running type-2 hypervisors and are normally reserved for client systems or end-user systems.
These solutions are often used because the cost of entry is significantly less. Sometimes, IT professionals use type-2 virtual servers to create virtual desktops.
There is a possible third option; para-virtualization. Para-virtualization also uses a hypervisor, but the virtual servers do not fully emulate the physical host’s hardware. Instead, a para-virtualization hypervisor will take advantage of an application programming interface (API) – typically integrated into modern servers – and it directly exchanges calls to the host and virtual server operating systems. The resulting virtual servers recognize their environment as an extension of the host’s resources.
There are different ways to manage and maintain your virtual server but here are some of the best practices that I’ve found over the past 20 years:
Virtual desktops are the technology that allows for different operating systems to run on the same desktop, or virtual computers running on a virtual machine elsewhere for the explicit use of that one user. An example of a virtual desktop is Citrix and Windows 365.
Virtual servers provide the ability to pool physical resources to provide a hypervisor under this infrastructure. You can have virtual desktops running on a virtual server, but it would be very rare to see virtual servers running within a virtual desktop.
A good place to start is getting to grip on how virtual technology works is diving straight in. To understand more about type-1 virtual servers, VMWare ESXi can be used free of charge for a period of time and built upon a magnitude of hardware to get an understanding of how the solution works.
Also, building up your knowledge of virtual networking, VMware vSphere, and completing physical to virtual migrations. If you would like to know more about how to run a type-2, Oracle VM VirtualBox provides an open-sourced hosted hypervisor that runs on a host operating system to support guest virtual machines.