Oracle (s ORCL) today said it would buy Virtual Iron, a startup that has built a suite of virtualization software based on the Xen hypervisor. Terms of the deal were undisclosed, but Virtual Iron has raised more than $65 million in venture capital. The company’s products compete against VMWare (s vmw), Microsoft’s (s MSFT) Hyper-V and Citrix (s CTXS) XenServer. But it’s odd that Oracle, with its own Xen-based hypervisor, and as the soon-to-be owner of Sun’s xVM virtualization products (which also include a Xen-based hypervisor), felt the need for a third virtualization product. Is it cobbling all of these different hypervisors and software together for a full-on assualt on the virtualization market?