Logical Domains
Encyclopedia
Logical Domains is the server virtualization and partitioning technology
from Sun Microsystems
released in April 2007. It has been re-branded as Oracle VM Server for SPARC since Oracle Corporation
completed the acquisition of Sun in January 2010.
Each domain is a full virtual machine with a reconfigurable subset of hardware resources. Operating system
s running inside Logical Domains can be started, stopped, and rebooted independently.
, the UltraSPARC T2
, the UltraSPARC T2 Plus and the SPARC T3 . Only systems based on those processors support Logical Domains. These include the UltraSPARC T1-based:
UltraSPARC T2-based:
UltraSPARC T2 Plus systems:
And SPARC T3 systems :
Logical Domains exploits the "Chip Multi Threading" (CMT) nature of the UltraSPARC T1, T2, and SPARC T3 processors. A single chip contains up to 16 CPU cores, and each core has either four hardware threads
(for the T1) or eight hardware threads (for the T2, T2+ and T3) that act as virtual CPUs. All CPU cores execute instructions concurrently, and each core switches between threads—typically when a thread stalls on a cache miss or goes idle—within a single clock cycle. This lets the processor gain throughput that is lost during cache misses in conventional CPU designs.
Each processor can support as many as one domain per hardware thread—up to 32 domains for the UltraSPARC T1, 64 domains for the UltraSPARC T2, and 128 domains for UltraSPARC T2+ servers with two physical processors or any number of SPARC T3 processors. Alternatively, and in usual practice, a given domain can be assigned multiple CPU threads for additional capacity within a single OS instance. CPU threads and virtual I/O devices can be added to or removed from a domain by administrator command in the control domain. This change takes effect immediately without needing to reboot the affected domain, which can immediately make use of added CPU threads or continue operating with reduced CPU threads.
The Control domain, as its name implies, controls the logical domain environment. It is used to configure machine resources and guest domains, and provides services necessary for domain operation, such as virtual console service. The control domain also normally acts as a service domain.
Service domains present virtual services, such as virtual disk drives and network switches, to other domains. In most cases, guest domains perform I/O via bridged access through services domains, which are directly connected to the physical devices. Service domains can provide virtual LANs and SANs as well as bridge through to physical devices. Disk images can reside on complete physical disks, slices (partitions of a disk), or even on files contained on a UFS
or ZFS
filesystem. Current processors can have two service domains in order to provide resiliency against failures.
I/O domain has direct ownership of and direct access to physical I/O devices, such as a network card in a PCI controller. It shares the devices to other domains in the form of virtual devices. You can have a maximum of two I/O domains for the UltraSPARC T1 (Niagara) servers, one of which also must be the control domain. UltraSPARC T2 Plus and SPARC T3 servers can have as many as 4 I/O domains.
Guest domains run an operating system instance without performing any of the above roles, but leverage the services provided by the above in order to run applications.
Control and service functions can be combined within domains, however it is recommended that user applications not run within control or service domains in order to protect domain stability and performance.
Paravirtualization
In computing, paravirtualization is a virtualization technique that presents a software interface to virtual machines that is similar but not identical to that of the underlying hardware....
from Sun Microsystems
Sun Microsystems
Sun Microsystems, Inc. was a company that sold :computers, computer components, :computer software, and :information technology services. Sun was founded on February 24, 1982...
released in April 2007. It has been re-branded as Oracle VM Server for SPARC since Oracle Corporation
Oracle Corporation
Oracle Corporation is an American multinational computer technology corporation that specializes in developing and marketing hardware systems and enterprise software products – particularly database management systems...
completed the acquisition of Sun in January 2010.
Each domain is a full virtual machine with a reconfigurable subset of hardware resources. Operating system
Operating system
An operating system is a set of programs that manage computer hardware resources and provide common services for application software. The operating system is the most important type of system software in a computer system...
s running inside Logical Domains can be started, stopped, and rebooted independently.
Supported hardware
The SPARC Hypervisor runs in the Hyper-Privileged execution mode, which was introduced in the sun4v architecture. The sun4v processors released as of September 2010 are the UltraSPARC T1UltraSPARC T1
|right|262px|UltraSPARC T1 processorSun Microsystems' UltraSPARC T1 microprocessor, known until its 14 November 2005 announcement by its development codename "Niagara", is a multithreading, multicore CPU...
, the UltraSPARC T2
UltraSPARC T2
Sun Microsystems' UltraSPARC T2 microprocessor is a multithreading, multi-core CPU. It is a member of the SPARC family, and the successor to the UltraSPARC T1. The chip is sometimes referred to by its codename, Niagara 2...
, the UltraSPARC T2 Plus and the SPARC T3 . Only systems based on those processors support Logical Domains. These include the UltraSPARC T1-based:
- Sun / Fujitsu SPARC EnterpriseSPARC EnterpriseThe SPARC Enterprise series is a range of UNIX server computers co-developed by Sun Microsystems and Fujitsu introduced in 2007. They are marketed and sold by Sun Microsystems , Fujitsu, and Fujitsu Siemens Computers under the common brand of SPARC Enterprise, superseding Sun's Sun Fire and...
T1000 and T2000 servers - Sun FireSun FireThe Sun Fire server brand is a series of server computers introduced in 2001 by Sun Microsystems . The Sun Fire branding coincided with the introduction of the UltraSPARC III processor, superseding the UltraSPARC II-based Sun Enterprise series...
T1000 and T2000 servers - Netra T2000 Server
- Netra CP3060 Blade
- Sun Blade T6300 Server Module
UltraSPARC T2-based:
- Sun / Fujitsu SPARC Enterprise T5120 and T5220 servers
- Sun Blade T6320 Server Module
- Netra CP3260 Blade
- Netra T5220 Rackmount Server
UltraSPARC T2 Plus systems:
- Sun / Fujitsu SPARC Enterprise T5140 and T5240 servers (2 sockets)
- Sun Blade T6340 Server Module (2 sockets)
- Sun / Fujitsu SPARC Enterprise T5440 (4 sockets)
And SPARC T3 systems :
- Sun / Fujitsu SPARC T3-1 servers (1 socket)
- Sun SPARC T3-1B Server Module (1 socket)
- Sun / Fujitsu SPARC T3-2 servers (2 sockets)
- Sun / Fujitsu SPARC T3-4 servers (4 sockets)
Logical Domains exploits the "Chip Multi Threading" (CMT) nature of the UltraSPARC T1, T2, and SPARC T3 processors. A single chip contains up to 16 CPU cores, and each core has either four hardware threads
Thread (computer science)
In computer science, a thread of execution is the smallest unit of processing that can be scheduled by an operating system. The implementation of threads and processes differs from one operating system to another, but in most cases, a thread is contained inside a process...
(for the T1) or eight hardware threads (for the T2, T2+ and T3) that act as virtual CPUs. All CPU cores execute instructions concurrently, and each core switches between threads—typically when a thread stalls on a cache miss or goes idle—within a single clock cycle. This lets the processor gain throughput that is lost during cache misses in conventional CPU designs.
Each processor can support as many as one domain per hardware thread—up to 32 domains for the UltraSPARC T1, 64 domains for the UltraSPARC T2, and 128 domains for UltraSPARC T2+ servers with two physical processors or any number of SPARC T3 processors. Alternatively, and in usual practice, a given domain can be assigned multiple CPU threads for additional capacity within a single OS instance. CPU threads and virtual I/O devices can be added to or removed from a domain by administrator command in the control domain. This change takes effect immediately without needing to reboot the affected domain, which can immediately make use of added CPU threads or continue operating with reduced CPU threads.
Logical Domain roles
All logical domains are the same except for the roles that you specify for them. There are multiple roles that logical domains can perform such as:- Control domain
- Service domain
- I/O domain
- Guest domain
The Control domain, as its name implies, controls the logical domain environment. It is used to configure machine resources and guest domains, and provides services necessary for domain operation, such as virtual console service. The control domain also normally acts as a service domain.
Service domains present virtual services, such as virtual disk drives and network switches, to other domains. In most cases, guest domains perform I/O via bridged access through services domains, which are directly connected to the physical devices. Service domains can provide virtual LANs and SANs as well as bridge through to physical devices. Disk images can reside on complete physical disks, slices (partitions of a disk), or even on files contained on a UFS
Unix File System
The Unix file system is a file system used by many Unix and Unix-like operating systems. It is also called the Berkeley Fast File System, the BSD Fast File System or FFS...
or ZFS
ZFS
In computing, ZFS is a combined file system and logical volume manager designed by Sun Microsystems. The features of ZFS include data integrity verification against data corruption modes , support for high storage capacities, integration of the concepts of filesystem and volume management,...
filesystem. Current processors can have two service domains in order to provide resiliency against failures.
I/O domain has direct ownership of and direct access to physical I/O devices, such as a network card in a PCI controller. It shares the devices to other domains in the form of virtual devices. You can have a maximum of two I/O domains for the UltraSPARC T1 (Niagara) servers, one of which also must be the control domain. UltraSPARC T2 Plus and SPARC T3 servers can have as many as 4 I/O domains.
Guest domains run an operating system instance without performing any of the above roles, but leverage the services provided by the above in order to run applications.
Control and service functions can be combined within domains, however it is recommended that user applications not run within control or service domains in order to protect domain stability and performance.
Supported guest operating systems
- Solaris 10 11/06 or later
- OpenSolarisOpenSolarisOpenSolaris was an open source computer operating system based on Solaris created by Sun Microsystems. It was also the name of the project initiated by Sun to build a developer and user community around the software...
2009.06 release - Ubuntu Linux Server Edition
- FreeBSDFreeBSDFreeBSD is a free Unix-like operating system descended from AT&T UNIX via BSD UNIX. Although for legal reasons FreeBSD cannot be called “UNIX”, as the direct descendant of BSD UNIX , FreeBSD’s internals and system APIs are UNIX-compliant...
(under development) - OpenBSDOpenBSDOpenBSD is a Unix-like computer operating system descended from Berkeley Software Distribution , a Unix derivative developed at the University of California, Berkeley. It was forked from NetBSD by project leader Theo de Raadt in late 1995...
4.5 or later - Wind RiverWind River SystemsWind River Systems, Inc. is a company providing embedded systems, development tools for embedded systems, middleware, and other types of software. The company was founded in Berkeley, California in 1981 by Jerry Fiddler and David Wilner. On June 4, 2009, Wind River announced that Intel had bought...
Platform for Network Equipment, Linux Edition (announced availability: second half of 2007)
External links
- Virtualization Solutions from Oracle
- Logical Domains at Sun.COM
- Logical Domain Manager Software at Fujitsu
- Logical Domains at BigAdmin System Administration Portal
- Sun BluePrint: Beginners Guide to LDoms: Understanding and Deploying Logical Domains
- Sun BluePrint: Energy Efficiency Strategies: Sun Server Virtualization Technology
- Sun BluePrint: Using Logical Domains and CoolThreads Technology: Improving Scalability and System Utilization
- Sun Virtualization Solutions
- Logical Domains Community at OpenSolaris.org
- Libvirt for LDoms, see documentation
- Logical Domains (LDoms) - presented at the OpenSolarisOpenSolarisOpenSolaris was an open source computer operating system based on Solaris created by Sun Microsystems. It was also the name of the project initiated by Sun to build a developer and user community around the software...
usergroup meeting