[opensource] Virtualization Technologies (Xen)
dinan at cse.ohio-state.edu
Thu Oct 19 14:04:45 EDT 2006
> Does anybody have any links or documentation for installing Xen on an
> existing CentOS server so I can install other CentOS servers on top of
> it for separating Webserver with DNS?
> Also, is it advisable to use Xen or should I use VMWare if I intend to
> use virtualization for a small business?
> Thanking you in advance for your efforts in helping me.
You can get commercial support for Xen through Xen Source. Xen also has
lots of corporate backing including Intel, AMD, and Microsoft. However,
Xen relies on paravirtualization which means the guest operating systems
need to be modified to cooperate with Xen. In the context of Linux,
this is no problem and it's easy to get linux guests running inside Xen.
However, windows is not yet available as a Xen guest (hopefully soon).
VMWare uses a different approach where it modifies the binary image in
memory, allowing you to run pretty much any OS unmodified. This is
slower but more flexible for legacy OSes. So, if you absolutely need to
run windows on one of your VMs Xen may not be the right choice at present.
The reason you have to fiddle with the OS is because the x86 has not
traditionally been designed to be compatible with virtualization. Now
that Intel and AMD have introduced virtualization-friendly extensions in
their latest chips, I would expect these restrictions to change. Also,
if you do purchase a system that you plan to run a VMM on, make sure it
has a CPU that supports these extensions.
Documentation for Xen is available here:
Best of luck,
James Dinan <dinan at cse.ohio-state.edu>
Graduate RA - Computer Science and Engineering
The Ohio State University
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