by
Steven "Warren MCSE, MCDBA" | Nov 25, 2003
Takeaway: Virtual machines appear to be part of the next wave of
server-based computing, and VMware remains the leading provider of this
technology. Learn the distinctions between VMware's Workstation, GSX
Server, and ESX Server products.
Main:VMware Workstation and its virtual computing technology have changed
the way most companies look at test environments, and in some cases,
even production environments. However VMware Workstation isn’t the only
technology that
VMware
has to offer. The company also offers GSX Server and now ESX Server as
well. Let's look at how to best leverage these technologies in your
company.
VMware WorkstationVMware Workstation
uses virtual machine technology that is designed mostly for the power
user. It allows you to run multiple operating systems on a single PC.
The operating systems that can run under a VMware virtual machine can
include Windows 2000, Windows XP, Windows 2003 Server, Novell Netware,
and Linux.
After running through a simple installation of VMware
Workstation, you have the ability to configure virtual machines within
VMware’s interface. These virtual machines act and look just like a
real computer, except they sit inside a window (
Figure A).
| Figure A |
 |
In
addition, you can network these computers, join and disjoin them from a
domain, connect to the Internet and other networks from within them,
and simulate whatever environment you choose.
On one of my
computers, I've used VMware Workstation to simulate an entire Windows
2003 network with Windows XP clients. With this environment, I can test
all of the Windows 2003 product line for compatibility with my network,
as well as study for my Windows Server 2003 certification exams. In the
past, I had to have at least three systems to be able to accomplish
this kind of testing. Now all I need is one computer, an Internet
connection, and VMware Workstation.
How does this work?
VMware works simultaneously with your operating system to allow you to
host multiple virtual machines. It does this by allowing you to
configure your virtual machines on the VMware virtualization layer.
This layer lets you map your hardware to the virtual machine's
resources and have virtual machines mapped to your floppy drive, hard
drive, CPU, etc. Inside each virtual machine, you can create virtual
hard disks and specify how much RAM you want to allocate to each of
your virtual machines. Plus, each virtual machine can have its own IP
address, even if the system hardware has only one network adapter.
In most of the environments I've
seen, VMware Workstation is typically used to configure test
environments, software development testing, training classrooms, and
technical support (to simulate the environment of the user). Now that
you've seen how the power user can use VMware, let’s examine how VMware
can meet the enterprise server and mainframe needs of your company.
VMware GSX ServerI recently was given the opportunity to evaluate
VMware GSX Server,
and I was impressed by how well it worked. VMware Workstation supports
only one CPU and up to 1 GB of RAM. GSX Server supports 2 CPUs and up
to 2 GB of RAM. GSX Server is very similar to Workstation in most other
ways, but one of its coolest features is the Remote Console that allows
you to remotely manage and access your virtual machine from anywhere on
your network. In addition, it's much easier to work with in a high
availability configuration.
While VMware Workstation is mostly
used by a single user to run multiple instances of operating systems
for testing and support purposes, GSX Server is often used for server
consolidation by running virtual machines of server operating systems
that simply appear to be stand-alone servers to clients on the network.
VMware ESX ServerVMware ESX Server
is mainframe-class virtual machine software. This solution is typically
used by mainframe data centers and cutting-edge companies. I've also
seen this solution used by startup companies. With ESX Server, you can
do amazing things such as more extensive server consolidation and
virtual machine clustering.
How does it differ from GSX Server and VMware Workstation?With
VMware Workstation and GSX Server, the software sits on top of a host
operating system such as Windows or Linux. With ESX Server, the
software runs directly on the system's hardware, eliminating the need
to install a base OS. In fact, ESX has its own OS. The software
basically runs on its own Linux kernel, and Linux is quite beneficial
to know when working with the product, although it's not an absolute
necessity.
Installation of this product is quite basic. You
place the CD in the tray of a system and boot from the CD. It runs you
through a typical Linux installation. At the end of the install, you're
instructed to go to a separate machine and type in a specific Web
address to access the virtual console of ESX Server. From there, you'll
configure your system and create virtual machines. With ESX Server, you
can have up to 3.6 GB of RAM per virtual machine as well as high
performance network cards.
How are companies using ESX Server?What
I really like about this product is how companies are using it. For
example, I've seen startups simply purchase a SAN and ESX Server and
create their whole network using ESX Server. This includes the servers
and workstations, which are accessed with thin clients.
GSX
Server is lightning fast, so you can’t tell the difference between real
systems and its virtual systems (if you have powerful hardware running
GSX Server). Furthermore, I've seen data centers use ESX Server for
hosting client environments and test environments. In the future, I
think more companies will take advantage of ESX Server as part of their
business strategy.
Final analysisVirtual
machine technology is becoming more and more mainstream in today’s IT
marketplace. With the current trend toward consolidating servers,
VMware is quickly making a place for its products in the server room.
Microsoft has even taken an interest in the virtual machine market by
buying
Virtual PC.
However, Microsoft's product line doesn’t quite have the maturity of
the VMware product line when it comes to providing enterprise-class
server solutions.
