38 SPARC Enterprise T5440 Server Administration Guide • July 2009
■“Logical Domain Configurations” on page 39
■“Logical Domains Software Requirements” on page 39
Logical Domain Software Overview
Logical Domains (LDoms) software enables you to allocate the system resources of
your server (such as a boot environment, CPUs, memory,and I/O devices) into
logical domains. By using a logical domains environment, you can increase resource
usage, improve scaling, and gain greater control of security and isolation
LDoms software enables you to create and manage as many as 128 logical domains,
depending on the hardware configuration of the server on which the Logical
Domains Manager has been installed. You can virtualize resourcesand define
network, storage, and other I/O devices as services that can be shared between
domains.
A logical domain is a discrete logical grouping with its own operating system,
resources, and identity within a single computer system. Applications software can
run in logical domains. Each logical domain can be created, destroyed, reconfigured,
and rebooted independently.There are several roles that logical domains can
perform as shown in the following table.
TABLE: Logical Domain Roles
Domain Role Description
Control domain Domain in which the Logical Domains Manager runs, enabling you to
create and manage other logical domains and allocate virtual resourcesto
other domains. There can be only one control domain per server.The
initial domain created when installing LDoms software is a control
domain and is named primary.
Service domain Domain that provides virtual device services to other domains, such as a
virtual switch, a virtual console concentrator,and a virtual disk server.
I/O domain Domain that has direct ownership of and direct access to physical I/O
devices, such as a network card in a PCI Express controller.Shares the
devices with other domains in the form of virtual devices. Youcan have a
maximum of two I/O domains, one of which also must be the control
domain.
Guest domain Domain that is managed by the control domain and uses services from the
I/O and service domains.