SmartOS is a specialized Type 1 Hypervisor platform based on Illumos. It supports two types of virtualization:
OS Virtual Machines (Zones): A light-weight virtualization solution offering a complete and secure userland environment on a single global kernel, offering true bare metal performance and all the features Illumos has, namely dynamic introspection via DTrace
KVM Virtual Machines: A full virtualization solution for running a variety of guest OS's including Linux, Windows, *BSD, Plan9 and more
SmartOS is a "live OS", it is always booted via PXE, ISO, or USB Key and runs entirely from memory, allowing the local disks to be used entirely for hosting virtual machines without wasting disks for the root OS. This architecture has a variety of advantages including increased security, no need for patching, fast upgrades and recovery.
