end of the line, and lower capital costs, higher asset utilization, and lower availability at the other end. Virtualization can enhance availability.
GUSTAV You will tend to use the VM, because while there
are differences now at the hypervisor level, those differences are converging relatively rapidly and will ultimately
If you’re worried about the long-term trend of hypervisors, you’re worried about the wrong thing. Choose the
VM that is most compatible today to the application you
are going to run. If you’re doing desktop virtualization,
you’re probably going to use CXD (Citrix Xen Desktop).
If you’re doing Windows server virtualization, you’re
going to use either Veridian or, depending on what you’re
trying to do regarding availability management, VMware.
The first question to ask is, “What are you used to?”
That’s going to determine what your likely VM is. The
second question is, “What is the problem you’re trying
to solve?” The more complex the management problem,
the more attractive an integrated tool suite from VMware
becomes. If you are saying, “I don’t have complex
problems now but I’m going to have complex problems
in three or four years,” the more attractive Microsoft
becomes. If you are going to build it on your own and/or
have your own toolsets to integrate, which is most of the
enterprise, you’re going to find the Xen/Citrix option
more attractive. If you’re coming from the desktop side,
you’re at the other side of Citrix, and that is back to Xen.
Where you’re coming from is going to determine your
VM product selection much more than where you’re
going, because they’re all heading to the same place.
CROSBY Both Microsoft Hyper-V/System Center and
VMware VSX and VC are complete architectures. Neither
of them has a well-established ISV (independent software vendor) ecosystem significantly limiting customer
choices. That said, I think the ecosystem around VMware
is now starting to emerge as a result of the adoption of
What worries me is whether the missing functionality in any vendor’s product needs to be developed by the
vendor or whether the customer is OK with a solution
composed of a vendor product and ISV add-ons. Both
Stratus and Marathon offer fault-tolerant virtual machine
infrastructure products using Citrix XenServer as an
embedded component. That’s because they focus on how
to build the world’s best fault tolerance, whereas Citrix,
VMware, and Microsoft do not. We have an open architecture, and that allows the world’s best talent to look
at how to extend it and build solutions beyond our core
competence. This is a very powerful model.
From an architectural perspective, I am absolutely passionate that virtualization should be open because then
you get this very powerful model of innovation.
I have an ongoing discussion with one of the major
analyst organizations because virtualization in their
brains is shaped like VMware’s products are shaped today.
They think of it as ESX Server. If VMware’s ESX Server
is viewed as a fully integrated car, then Xen should be
viewed as a single engine. I would assert that because we
don’t know where virtualization is going to be in five
years, you do not want to bind your consumption of
virtualization to a particular car right now. As technology innovation occurs, virtualization will take different
shapes. For example, the storage industry is innovating rapidly in virtualization, and VMware cannot take
advantage of it with its (current) closed architecture. Xen
is open and can adapt. It runs on a 4,096-CPU supercom-puter from SGI, and it runs on a PC. That is an engine
story; it is not a car story.
It’s really critical that we have an architecture that
allows independent innovation around the components
of virtualization. Virtualization is just a technology for
forcing separation as far down the stack as you can—on
the server, separated by the hypervisor, in the storage
system—and then let’s see how things build. I’m not in
favor of any architecture that precludes innovation from
a huge ecosystem.
HERROD I actually agree on several parts. Especially for
the middle market, the number-one thing that people
need is something easy to use. I think there’s a reasonable
middle road that can provide a very nice framework or a
common way of doing things, but also have tie-in to the
partner ecosystem. Microsoft has done this very well for a
BOURNE These bindings may be ABIs (application binary
interfaces) or they may not be, but they sound like the
analogue of the ABIs. ABIs are a pain in the neck. So are
these bindings a pain in the neck?
CROSBY Bindings are a very hot area. The hottest one
for us right now is that the VM you run on XenServer
will run on Microsoft Hyper-V. This is a virtual hardware
interface, where, when you move a virtual machine from
one product to the other, the VM will still think it has the
same hardware underneath it.
If you take a VM from VMware and try to run it on
Citrix, you will get a blue screen. It’s just the same as if
you took a hard disk out of a server and put it in another
server and expected the operating system to boot cor-