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. Virtualization in SmartOS builds on top of the foundational Illumos technologies inherited from OpenSolaris, namely:

ZFS for storage virtualization Crossbow (dladm) for network virtualization Zones for virtualization and containment DTrace for introspection SMF for service management RBAC/BSM for auditing and role based security etc.

These technologies are combined into a single operating system, providing an arbitrarily-observable, highly multi-tenant environment built on a reliable, enterprise-grade storage stack.