If you read my blog you know this: this month press is totally crowded by articles about XEN and Virtual Iron. Many writers are pointing out that after years of predominance, now VMware has a lot of important competitors that offer same or better virtualization tecnologies.
My personal opinion is that nothing of this can be said today.
While XEN and Virtual Iron are interesting virtualization projects, today both offers just Linux virtualization, while VMware is extending it’s guest operating systems list with most wanted SUN Solaris, apart Windows, Linux, BSD and Netware already supported OS families.
Till XEN or Virtual Iron won’t offer support for at least Windows guest OS, then will be not comparable with VMware at all. Today the only real VMware competitor is SVISTA, and Microsoft Virtual PC/Server (considering we know they can run *nix guest OS, even if not supported).
If XEN and Virtual Iron will just offer Linux guest OSes in future, then will compete much more with virtualization solutions like Virtuozzo (even if base technology is different). And actually their best competitor is the just launched Container technology on Sun Solaris 10.
The problem is: who’ll adopt XEN that obliges to modify guest OS kernels, or Virtual Iron that is a commercial product when Sun offers a native software partitioning at zero cost (even for commercial projects), embedded in its operating system?