A logical domain (LDom) is a full virtual machine that runs an independent operating system instance and contains virtualized CPU, memory, storage, console, and cryptographic devices. Within the logical domains architecture, the hypervisor is a small firmware layer that provides a stable, virtualized machine architecture to which an operating system can be written. As such, each logical domain is completely isolated and the maximum number of virtual machines created on a single platform relies upon the capabilities of the hypervisor as opposed to the number of physical hardware devices installed in the system.
Solaris LDoms technology is supported on Sun servers which utilize UltraSPARC T1, T2, T3 or T4 processors. For example, Sun Fire T1000 and T2000 servers with a single Sun UltraSPARC T1 processor support up to 32 logical domains, and each individual logical domain can run a unique instance of operating system.
Taking advantage of LDoms provides the flexibility to deploy multiple operating systems simultaneously on a single platform. In addition, administrators can leverage virtual device capabilities to transport an entire software stack hosted on a logical domain from one physical machine to another. Logical domains can also host Solaris Containers to capture the isolation, flexibility, and manageability features of both technologies.