Virtualization queries

Question

I am virtualization newbie. Please advise on these questions. Please note using a commercial VM software like Citrix or VMware is not a choice for me.

I have at my disposal couple 2x 4 core servers with 32 GB RAM. I need to create 16 VMs on each of this server, to test some web applications

1) Can I provision a 1/2 core as virtual CPU for each VM. To my best knowledge I can't do so on Xen. is it possible on KVM or some other free open source VM solution?

2) If its not possible to assign half a core, how do I ensure that uniform processing power is available for all VMs

3) Since the job is to create seperate instances for hosting 16 web apps in a physical server, do you recommend setting up a private cloud using Ubuntu Enterprise Cloud as a better option?

4) Is there HA solution under KVM, like Remus for Xen?

I know questions are very related. Nevertheless I appeal for some advice

Answer 1

16 Servers does not seem to be too much - especially when using XEN and para-virtualization.

If I were you I would assign 2 CPUs to each of your VMs. The Hypervisor will handle fair CPU scheduling.

Most propably the 16 VMs will not use the whole 8 cores (HT?) at the same time.

Top within your DomUs will show you if processor time gets stolen...