Basic virtualisation terminology

What is a hypervisor? What is vSphere vMotion? What is HA? Bryan O'Connor, our vExpert, decodes commonly used virtualisation terms.

Have you ever been sat and listened to someone talk, and they’re throwing acronyms and terminology at you, and you’ve thought, “Brilliant, but I have no idea what they’re talking about?”

After teaching and presenting VMware courses and Microsoft Hyper-V courses at QA for approaching 14 years, I’m probably one of those people throwing the acronyms and terminology at you.

Virtualisation is made up, or associated with, some key concepts, products and features. In this post, I outline some of the most used terminology in virtualisation, which certainly I use, and hopefully this will help the next time you’re sat listening to a talk on virtualisation.

Virtualisation terminology:

Operating system: Software designed to allocate physical resources to applications. Think of Microsoft Windows, Linux or MacOS.

Application: Software that runs on an operating system, consuming physical resources. Think of Chrome, Firefox, Microsoft Office.

Virtual machine (VM): Specialised application that abstracts hardware resources into software; basically a computer that is just a load of files. This could be anything that allows your business to run, such as your database server. Read more about virtual machines here.

Guest: The operating system that runs in a VM, also called the guest operating system. Think of a virtual machine running Microsoft Windows Server.

Hypervisor: Specialised operating system designed to run VMs. Think of VMware ESXi or Microsoft Hyper-V.

Host: Physical computer that provides the hardware resource to the hypervisor. Common manufacturers are HP, Dell and IBM.

Hypervisor terminology:

Once we have our product installed, we also have some hypervisor-specific terms in place.

vSphere, Hyper-V: vSphere is the server virtualisation product of VMware that combines the ESXi hypervisor and the vCenter Server management platform. Hyper-V is the server virtualisation product of Microsoft.

Cluster: Group of ESXi or Hyper-V hosts whose resources are shared by VMs.

vSphere vMotion, Hyper-V Live Migration: Feature that supports the migration of powered-on VMs from host to host without service interruption.

vSphere storage vMotion, Hyper-V Live Migration: Feature that supports the migration of powered on VMs files from datastore to datastore without service interruption.

HA (high availability): Cluster feature that protects against host hardware failures by restarting VMs on hosts that are running normally.

vSphere DRS (dynamic resource scheduler): Cluster feature that uses vSphere vMotion to place VMs on hosts and ensure that each VM receives the resources that it needs; also the feature that dynamically load-balances VMs between hosts to ensure reliability and performance of VMS.

 I hope this helps to decode the most commonly used virtualisation terms. Click here if you're interested in our extensive range of VMware virtual machine courses.


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