A Beginners Guide to LDom  Sun Microsystems’ Logical Domains (LDoms) technology “provides the ability to split a single physical system into multiple, independent virtual systems.” (BEGINNERS GUIDE TO LDOMS: UNDERSTANDING AND DEPLOYING LOGICAL DOMAINS http://www.sun.com/blueprints/0207/820-0832.pdf) In effect, one machine is able to support multiple systems running CPUs, memory, and devices, each independent and secure from one another. Security, scaling, kernel management, patch sets, and packages can be applied to individual systems as required. There are other ways to partition systems, such as Solaris Containers, Solaris Resource Management, Sun Fire Domains and XVM. LDoms are ideal for environments requiring management for multiple kernels, or increased security between servers. However, a huge benefit is the reduction in administrative support as a result of the management of one kernel image. What makes this technology possible is the hypervisor, a software layer between the operating system and hardware. It is the hypervisor’s ability to act on behalf of the OS to manage and control hardware that enables this technology. Ultimately, with this consolidation of resources, data centers are not only more efficient; costs can be significantly reduced.  There are four types of domains, the Control Domain, Service Domain, I/O Domain, and Guest Domain. The first domain to be installed is the Control Domain. This is where the Logical Domain Manager resides and is responsible for communications with the hypervisor. The Service Domain shares the virtualized services, such as network switches. The I/O domain controls and shares physical hardware devices when needed. The guest domain is where the virtualized systems are located, and reports to the Control Domain. “The guest domain must run an operating system that understands both the sun4v platform and the virtual devices presented by the hypervisor. Currently, this is the Solaris 10 11/06 OS with required patches 124921-02 and 125043-01 (with kernel update 118833-36) at a minimum.” (BEGINNERS GUIDE TO LDOMS: UNDERSTANDING AND DEPLOYING LOGICAL DOMAINS)

After the analysis of your system resources and desired configuration, you are ready to install and setup LDoms. How you setup and configure your system will depend on your specifications, however, at minimum you will have one Control Domain supporting one Guest Domain.