Desktop Virtualization:
Expert Guide to VDI,
Hypervisors, and More
Many businesses fail to understand that the desktop virtualization space
extends far beyond just VDI. This expert E-Guide, brought to you by
SearchVirtualDesktop.com, Dell, and Intel, explores often overlooked
aspects of desktop virtualization. Gain insight into the various forms of
desktop virtualization technologies currently available, including VDI,
terminal server, OS streaming, client hypervisors and client-based
vir-tual machines. Discover why bare-metal client hypervisors will soon be
mainstream and available for use in your virtual environment.
Virtualization Media
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Table of Contents
Table of Contents:
Desktop virtualization is more than VDI
Bare-metal client hypervisors are coming — for real this time
Resources from Dell, Inc. and Intel
Desktop Virtualization:
Expert Guide to VDI,
Hypervisors, and More
Desktop virtualization is more than VDI
By Brian Madden
The name of this website is "SearchVirtualDesktop," which implies that it covers… well… virtual desktops. But what exactly is a virtual desktop? A lot of people immediately think "VDI." But that's only partially right.
At its most basic level, "virtualization" is separating the "physical" from the "logical," so therefore "desktop virtual-ization" is separating the physical desktop device (laptop, desktop, etc.) from the logical desktop software
(Windows).
So it's true that VDI is a desktop virtualization -- but it's only one type of desktop virtualization. The entire desktop virtualization universe is much bigger than just VDI.
For example, Terminal Server (and the various Terminal Server-based solutions like Citrix XenApp) is desktop virtualization, since it provides a desktop to a user (from the remote server) to a user's device (like a thin client) where the desktop OS is not installed on the device.
In fact, from a user's standpoint, VDI and Terminal Server are just about identical. They are both server-based computing. They both use thin clients or remote connection software on fat clients. They both present a remote desktop to the user. The only difference between VDI and Terminal Server is on the back end, where VDI is a single-user remote user and Terminal Server is a multi-user remote host.
But, even though VDI and Terminal Server are both server-based computing forms of desktop virtualization, there are other types of desktop virtualization that don't use server-based computing at all.
For example, "OS streaming" describes a technology where a company of Windows runs locally on a client device (so "client-based computing" rather than "server-based computing"). But with OS streaming, the OS image is "streamed" from a central point down to the client rather than installed locally.
OS streaming works by performing a variant of the tried-and-true "network boot," where the client boots and mounts a desktop disk image from a server across the network. So this "counts" as desktop virtualization because even though the desktop software is physically running on the desktop device, it's all managed centrally as a disk image on a server. Since no software is installed on the client, it's virtualized.
OS streaming can be used "natively" on a client device -- where the only real change is that the copy of Windows is a shared copy coming across the network instead of installed locally -- or it can be used in combination with some kind of hardware virtualization running on the client device.
Combining hardware virtualization with client devices is a whole additional category of desktop virtualization. Citrix, VMware and startup companies Virtual Computer and Neocleus are all talking about “client hypervisors.” Client hypervisors are like VMware ESX or Microsoft Hyper-V for laptops, with the idea that a laptop could easily run one
Desktop virtualization is more than VDI
or more virtual machines, bringing the benefits of image portability, management and backup and control to laptops just like servers.
Finally, other companies, such as RingCube and Mokafive, have products which allow administrators to run central-ly-controlled corporate virtual machines directly on client devices on top of existing client operating systems (even Linux or Mac), combining user freedom of choice and administrator control.
So there you have it. VDI, terminal server, OS streaming, client hypervisors, client-based virtual machines -- these are all forms of desktop virtualization, and these are all things we're going to cover on SearchVirtualDesktop.com. Which technology will win? How do you decide which technology should be used in which case? Stay tuned!
Bare-metal client hypervisors are coming
—
for real this time
By Brian Madden, Independent Industry Analyst and Blogger
Many people (myself included) have said that 2010 will be the "year of the bare-metal client hypervisor." In other words, this is the year when we'll finally see products from mainstream vendors and customers really starting to adopt them.
A client hypervisor, if you're not familiar with the concept, is essentially a server hypervisor that lets one or more virtual machines run on a desktop or laptop computer.
"But wait," you might ask, "don't products like Microsoft Virtual PC and VMware Workstation already let users run multiple VMs on desktops and laptops?"
Yes, they do, but these products are known as "Type 2" virtual environments, where they let VMs run on top of existing applications. Bare-metal client hypervisors (a.k.a. "Type 1" hypervisors) run on the "bare metal." In other words, the hypervisor is the operating system, rather than an application installed on top of an existing OS. (For a more complete discussion of Type 1 versus Type 2 client virtualization environments, the pros and cons of each, and why someone would want a bare-metal client hypervisor, check out my SearchVirtualDesktop.com column from July 1.) And this is important, because next year is the year! But why?
In 2009, two startup companies released bare-metal client hypervisors--Neocleus and Virtual Computer. This is cool because it means that this stuff is actually shipping today. Unfortunately, not too many people have heard of either of these companies, and so most people are waiting to see what the big companies will do.
As I'm writing this in May 2010, Citrix just released a beta version of a bare-metal client hypervisor known as XenClient. (This was previously known as "Project Independence" if you'd like to Google it for more details.) And VMware has promised to release their own bare-metal client hypervisor later this year.
So what's the big deal? I've been playing with these things in one form or another for a while now, and there are some key differences between client hypervisors and server hypervisors.
First of all, the motivations behind these two technologies are completely different. Server hypervisors are designed to make VMs portable and increasing the utilization of physical hardware. Client hypervisors are intended to
increase the manageability of the client device and improve security by separating work and personal VMs. Server hypervisors have to be tuned for maximum simultaneous network, processor and disk I/O utilization. Client hypervisors have to be tuned for graphics, multimedia and wireless connectivity.
Server hypervisors only have to run on a narrow set of different preapproved hardware models. Client hypervisors should (ideally) run on just about anything.
Bare-metal client hypervisors are coming — for real this time
Server hypervisors are the dream of Intel because they push the processing capabilities to the limit, driving everyone to buy the latest and greatest. Client hypervisors -- well, I guess that's one thing that's the same for both!
The bottom line is that even though they're both called "Type 1" or "bare-metal hypervisors," there are some philosophical differences in how each came to be. (This could help explain why it has taken over five years to extend the Type 1 hypervisor concept from the server to the desktop.)
But I promise that 2010 will be the year that you start to see bare-metal client hypervisors in the mainstream, so you should think now about how these might help you your own environment.
Resources from Dell, Inc. and Intel
Desktop Virtualization: An Expert Guide to the Benefits and Challenges
15 Reasons why Desktop Virtualization Projects Fail
About Dell, Inc. and Intel:
Dell and Intel are strategic partners in delivering innovative hardware solutions to solve your most
challenging IT problems. Together we are delivering virtualization optimized solutions to maximize
the benefits of any virtualization project.
Resources from Dell, Inc. and Intel
