VMware ESXi and Microsoft Hyper V are two major products to achieve virtualization at server level. While VMware is the industry standard and market leader, Microsoft is not far behind. With clever pricing and long term strategy, Microsoft is only going to eat into VMware share.
Virtualization at Server level
Virtualization enables running of multiple computers or servers simultaneously on the same hardware. In case of virtual servers they can be anything, mail server, web hosting server and so on. A virtual server with all the OS and software installed to perform a particular role or task. If it a computer, then that can be pushed to clients who have a virtual computer at their disposal complete with the operating system and whatever software is required.
When a virtual server or computer is made available to client with all the requisite tools and software, we have a cloud computing platform ready. Virtualisation has given a big push to cloud computing.
To read more about virtualization and cloud computing check out this article.
Check out the comparison between the free options of each vendor.
VMware ESXi is the bare bones server OS which installs directly on a server. Once installed, it has to be accessed by the admin either through a client or through the Web Browser. VMware ESXi is also called VMware vSphere Hypervisor and the client software is VMware vSphere Client.
vSphere Hypervisor or ESXi provides only a basic functionality of virtualization. One can create or delete virtual machines and start or pause them. Backing up of virtual machines is also possible. But this free offering by VMware can help you at the most to run few virtual servers. This will definitely help you to optimise your server hardware and boost up performance. But as the numbers increase, you will have a hard time managing and monitoring the health of your virtual servers. You cannot do clustering and live backup. Also commercial desktop virtualization is out of your reach.
To manage large number of virtual servers and multiple ESXi installations, you need a more powerful management console. This is provided by the commercial product by VMware, vCenter Server. vCentre Server can function as a physical server, but better option is to install vCenter server as another virtual machine over ESXi. Earlier, vSphere client used to login into ESXi server, but now it will access the interface of vCenter Server for management of virtual servers, ESXi servers and virtualized desktops.
Desktop Virtualization or VMware Horizon View
The true power of virtualization is to provide virtual PCs to clients on demand basis. This way, your employees can carry their PC along with its data wherever they go. VMware Horizon View is a collection of software suites which develop an interface for you to design, create and deploy virtual PCs on demand. Features like backup, cloning and clustering are made available for easy administration.