We are looking at selling a product that would involve running centos 5.5 on a small HP ML110 server. Some of our clients might also have need of a windows server install so we are looking at potentially running the windows box as a vm. A lot of my experience of virtual machines has been with running fully virtualised machines on virtualbox.

As this is something that will be being used in a production environment, I am looking at using either vmware or Xen. I suppose I could stick with virtualbox, but I get the impression that Xen and vmware are more mature.

I installed vmware server 2 and had issues with ssl certificates on the management web-based app. Felt a bit flakey. Have done a fresh install of centos with the virtualisation software group and have been trying to create a paravirtualised machine using virt-manager but have been unable to create a windows vm. Having to boot off the network after sharing the DVD via nfs again feels a bit flakey and it wouldn't recognise either an xp or win 2008 r2 disk (recognised ubuntu and centos disks ok. Any suggestions why they weren't recognised would be appreciated). I will try and get hold of some different windows install disks, and I could just create fully virtualised machines (which I have done using those disks) but I liked the idea of them being paravirtual.

So what are peoples thoughts on vmware vs Xen? Are there other vmware products other than server 2 I should be looking at? Are they worth paying for? How noticeable is the performance hit on running a fully virtualised machine against a paravirtualised machine? Any thoughts on why Xen wouldn't recognise the windows install disks when tryn to create a paravirtual machine (the error was along the lines of "could not find installable distribution")? Are there only certain windows versions that will work? The host is 64 bit, not sure what vs the xp disk was.

Cheers,
Gileswr

if you want a basic centos based system, then you don't want any of these things. Just use KVM / Qemu, as it's already there in the kernel ready for you, is painfully simple (and shares a lot of common libraries with Xen) and is just kinda ace. You'd never want to paravirtualize if you can do hardware virtualization. It's not a preference thing, you would want to use hardware CPU extensions if possible.