[CentOS] OT: Why VM?

I have been working off and on with Xen and KVM on a couple of test
hosts for that past year or so and while now everything seems to
function as expected, more or less, I find myself asking the
question: Why?

We run our own servers at our own sites for our own purposes.  We do
not, with a few small exceptions, host alien domains.  So, while
rapidly provisioning or dynamically expanding a client's vm might be
very attractive to a public hosting provider that is not our
business model at all.

Why would a small company not in the public hosting business choose
to employ VM technology?  What are the benefits over operating
several individual small form factor servers or blades instead?  I
am curious because what I can find on the net respecting VM use
cases, outside of for public providers or application testing, seems
to me mostly puff and smoke.

This might be considered OT but since CentOS is what we use it seems
to me best that I ask here to start.

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James B. Byrne                mailto:ByrneJB at Harte-Lyne.ca
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