Leyne, Sean wrote:

> For my point of view, no you wouldn't -- using a VM solution
> would mean that you would care very little about the host OS.

And then goes on, in another email, to say:

> What version of VMWare was installed GSX (Free) or ESX v3.5
> or ESX v4.0 (AKA Sphere)?
>
> The specific version *does* matter.

and later again to say:

> That is the GSX/*Free* version... _Not_ VMWare best product*
>
> I used it to host the Firebird web and tracker VM and it was
> a *dog*.
>
> We use VMWare 3.5 on 2 hosts in the office and performance is
> *very good*.
>
> I have also used Sun's Virtualbox solution it is also good --
> a little poorer on the disk IO side.

I am something of a fan of virtual machines, having used them
for many years to aid development/testing etc. But the simple
truth is that you cannot (yet) claim that using VMs means you
dont have to care about the host OS. You have seen this for
yourself.

Yes a hypervisor type host (VMware ESX/ESXi etc) is probably
the best bet for server installations. With VMware Server
(and Workstation) you can run into some very "interesting"
situations. For example using an Ubuntu 64bit host with
VMware Workstation, if I configure an XP VM with dual CPUs
(on quad hardware) then all network access brings the VM to
a crawl. Even with just a single CPU setup the Ubuntu host
does not perform well (excessive CPU use). The exact same
setup (and hardware) using a WinXP 32bit host performs quite
well, but obviously nowhere near direct on hardware speeds.
[No this is not the known tcp-offload issue.]

The need to use a hypervisor to get better performance for
servers reduces the attraction of deploying applications by
VM. The clients receiving the deployment must already be
prepared to use (or already using) hypervisors to have the
necessary infrastructure to manage them. (It's not that
difficult but it is not something you can assume for all
sites.)


VMs are a great solution to many problems but I can certainly
relate to Lester's comment:

> VM is just another unnecessary layer in my book?

because it is certainly another layer, the "unnecessary" vs
necessary part is largely a client/implementation decision.

--
Geoff Worboys
Telesis Computing