[clug] Why virtual x86 machines?

[Robert Cohen]

On 20/08/2020 9:09 pm, Hugh Fisher via linux wrote:
> \
> Looking at these prices I understand why Intel want us to virtualise
> x86 CPUs and run multiple guest operating systems. I don't see why
> anyone else would want to.
>
> But since datacentres and cloud systems do use hypervisors I must be
> missing something. Anyone want to explain?
>
>

For serious virtualisation eg cloud provider, its all about density.
In a rack, you can stack say 10 blades with 2 CPU's each with 64 cores 
(128 with hyperthreading).
On that you can run 2000+ small VM's (1-2 vcpu's). Or 200 largish VM's 
(8 VCPU).

If you tried to do that without virtualisation, you'd need 200 racks for 
the small machines.
Assuming 10 physical machine in a rack.