LPAR
Encyclopedia
A logical partition, commonly called an LPAR, is a subset of computer's hardware resources, virtualized as a separate computer. In effect, a physical machine can be partitioned into multiple logical partitions, each hosting a separate operating system
.
s (virtual machines
in CP-40
and CP-67
) and in 1972 provided it for the S/370 as Virtual Machine Facility/370. IBM introduced the Start Interpretive Execution (SIE) instruction as part of 370-XA on the 3081, and VM/XA versions of VM
to exploit it. PR/SM is a type-1 Hypervisor based on the CP component of VM/XA
that runs directly on the machine level and allocates system resources across LPAR's to share physical resources. It is a standard feature on IBM System z machines.
The terms PR/SM and LPAR are often used interchangeably, including in IBM documentation. Formally, LPAR designates the logical partitioning function and mode of operation, whereas PR/SM is the commercial designation of the feature.
This technology was later developed separately by Amdahl
, and Hitachi Data Systems
for the mainframe
architecture ESA/390
in the mid 1980s; and continued by IBM for zSeries
and System z architectures. LPAR and PR/SM reconfigurations can be made without rebooting the computer, i.e., while some LPARs remain active. Reconfigurations can include changing channel path definitions and device definitions.
z/VM supports the z/Architecture HiperSockets function for high-speed TCP/IP communication among virtual machines and logical partitions (LPARs) within the same IBM zSeries server. This function uses an adaptation of the Queued-Direct Input/Output (QDIO) high-speed I/O protocol.
IBM later extended the idea to non-mainframe servers, such as the pSeries in October 2001 and iSeries, albeit with varying technical specifications. Multiple operating systems are compatible with LPARs, including z/OS
, z/VM
, z/VSE, z/TPF, AIX
, Linux
(including Linux on zSeries), and i5/OS. In storage systems
, such as the IBM TotalStorage DS8000, LPARs allow for multiple virtual instances of a storage array to exist within a single physical array.
On IBM mainframes, LPARs are managed by the PR/SM
facility. IBM mainframes operate exclusively in LPAR mode, even when there is only one partition on a machine. Multiple LPARs running z/OS can form a Sysplex or Parallel Sysplex
, whether on one machine or spread across multiple machines.
On IBM System P Power hardware
, LPARs are managed by the Power Hypervisor. The Hypervisor or PowerVM
acts as a virtual switch between the LPARs and also handles the virtual SCSI
traffic between LPARs. Micro-Partitioning
supports 10 times as many LPARs as processors with fractional allocations. It was introduced with the POWER5
processor. All IBM POWER5
and POWER6
systems may be partitioned. Note that a full system partition may be defined where all resources are consumed by a single partition. System P servers with PowerVM enabled allow LPARs with shared CPUs to delegate their unused cycles into the shared pool. Dedicated processors are not available for sharing. Unused cycles become available for other partitions and are governed by the parameters specified when the LPAR is defined. Changes to a running partition can be made dynamically up to the maximum value set, and down to the minimum value set in the active profile. The changing of resource allocations without restart of the logical partition is called dynamic logical partitioning
. IBM PowerVM
(formerly known as Advanced POWER Virtualization or APV
) is the licensed/purchased feature that enables the virtualization features on p4,5,6,7 series servers.
LPARs safely allow combining multiple test, development, quality assurance, and production work on the same server, offering advantages such as lower costs, faster deployment, and more convenience. IBM mainframe LPARs are Common Criteria EAL5 certifiable, equivalent to physically unconnected servers, so they support the highest security requirements, including military use. Nearly all IBM mainframes run with multiple LPARs with the IBM System z9 and IBM System z10
supporting up to 60 LPARs.
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...
.
History
IBM developed the concept of HypervisorHypervisor
In computing, a hypervisor, also called virtual machine manager , is one of many hardware virtualization techniques that allow multiple operating systems, termed guests, to run concurrently on a host computer. It is so named because it is conceptually one level higher than a supervisory program...
s (virtual machines
Virtual machine
A virtual machine is a "completely isolated guest operating system installation within a normal host operating system". Modern virtual machines are implemented with either software emulation or hardware virtualization or both together.-VM Definitions:A virtual machine is a software...
in CP-40
IBM CP-40
CP-40 was a research precursor to CP-67, which in turn was part of IBM's then-revolutionary CP[-67]/CMS – a virtual machine/virtual memory time-sharing operating system for the IBM System/360-67, and the parent of IBM's VM family. CP-40 ran multiple instances of client operating systems...
and CP-67
CP-67
CP-67 was the control program portion of CP/CMS, a virtual machine operating system developed for the IBM System/360-67 by IBM's Cambridge Scientific Center. It was a reimplementation of their earlier research system CP-40, which ran on a one-off customized S/360-40...
) and in 1972 provided it for the S/370 as Virtual Machine Facility/370. IBM introduced the Start Interpretive Execution (SIE) instruction as part of 370-XA on the 3081, and VM/XA versions of VM
VM (operating system)
VM refers to a family of IBM virtual machine operating systems used on IBM mainframes System/370, System/390, zSeries, System z and compatible systems, including the Hercules emulator for personal computers. The first version, released in 1972, was VM/370, or officially Virtual Machine Facility/370...
to exploit it. PR/SM is a type-1 Hypervisor based on the CP component of VM/XA
VM (operating system)
VM refers to a family of IBM virtual machine operating systems used on IBM mainframes System/370, System/390, zSeries, System z and compatible systems, including the Hercules emulator for personal computers. The first version, released in 1972, was VM/370, or officially Virtual Machine Facility/370...
that runs directly on the machine level and allocates system resources across LPAR's to share physical resources. It is a standard feature on IBM System z machines.
The terms PR/SM and LPAR are often used interchangeably, including in IBM documentation. Formally, LPAR designates the logical partitioning function and mode of operation, whereas PR/SM is the commercial designation of the feature.
This technology was later developed separately by Amdahl
Amdahl Corporation
Amdahl Corporation is an information technology company which specializes in IBM mainframe-compatible computer products. Founded in 1970 by Dr. Gene Amdahl, a former IBM employee, it has been a wholly owned subsidiary of Fujitsu since 1997...
, and Hitachi Data Systems
Hitachi Data Systems
Hitachi Data Systems is a company providing mid-range and high-end storage systems, software and services. It is a wholly owned subsidiary of Hitachi Ltd. and part of the Hitachi Information Systems & Telecommunications Division....
for the mainframe
Mainframe computer
Mainframes are powerful computers used primarily by corporate and governmental organizations for critical applications, bulk data processing such as census, industry and consumer statistics, enterprise resource planning, and financial transaction processing.The term originally referred to the...
architecture ESA/390
ESA/390
ESA/390 was introduced in September 1990 and is IBM's last 31-bit-address/32-bit-data mainframe computing design, copied by Amdahl, Hitachi, and Fujitsu among other competitors...
in the mid 1980s; and continued by IBM for zSeries
ZSeries
IBM System z, or earlier IBM eServer zSeries, is a brand name designated by IBM to all its mainframe computers.In 2000, IBM rebranded the existing System/390 to IBM eServer zSeries with the e depicted in IBM's red trademarked symbol, but because no specific machine names were changed for...
and System z architectures. LPAR and PR/SM reconfigurations can be made without rebooting the computer, i.e., while some LPARs remain active. Reconfigurations can include changing channel path definitions and device definitions.
z/VM supports the z/Architecture HiperSockets function for high-speed TCP/IP communication among virtual machines and logical partitions (LPARs) within the same IBM zSeries server. This function uses an adaptation of the Queued-Direct Input/Output (QDIO) high-speed I/O protocol.
IBM later extended the idea to non-mainframe servers, such as the pSeries in October 2001 and iSeries, albeit with varying technical specifications. Multiple operating systems are compatible with LPARs, including z/OS
Z/OS
z/OS is a 64-bit operating system for mainframe computers, produced by IBM. It derives from and is the successor to OS/390, which in turn followed a string of MVS versions.Starting with earliest:*OS/VS2 Release 2 through Release 3.8...
, z/VM
Z/VM
z/VM is the current version in IBM's VM family of virtual machine operating systems. z/VM was first released in October 2000 and remains in active use and development . It is directly based on technology and concepts dating back to the 1960s, with IBM's CP/CMS on the IBM System/360-67...
, z/VSE, z/TPF, AIX
AIX operating system
AIX AIX AIX (Advanced Interactive eXecutive, pronounced "a i ex" is a series of proprietary Unix operating systems developed and sold by IBM for several of its computer platforms...
, Linux
Linux
Linux is a Unix-like computer operating system assembled under the model of free and open source software development and distribution. The defining component of any Linux system is the Linux kernel, an operating system kernel first released October 5, 1991 by Linus Torvalds...
(including Linux on zSeries), and i5/OS. In storage systems
Disk array
A disk array is a disk storage system which contains multiple disk drives. It is differentiated from a disk enclosure, in that an array has cache memory and advanced functionality, like RAID and virtualization.Components of a typical disk array include:...
, such as the IBM TotalStorage DS8000, LPARs allow for multiple virtual instances of a storage array to exist within a single physical array.
Hardware partitioning
Logical partitioning divides hardware resources. Two LPARs may access memory from a common memory chip, provided that the ranges of addresses directly accessible to each do not overlap. One partition may indirectly control memory controlled by a second partition, but only by commanding a process in that partition. CPUs may be dedicated to a single LPAR or shared. While on Amdahl's MDF(Multiple Domain Feature) it was possible to configure an LPAR with both shared and dedicated CPUs. This is no longer possible with any mainframes flavours currently in the market.On IBM mainframes, LPARs are managed by the PR/SM
PR/SM
PR/SM is a type-1 Hypervisor that allows multiple logical partitions to share physical resources such as CPUs, I/O channels and direct access storage devices...
facility. IBM mainframes operate exclusively in LPAR mode, even when there is only one partition on a machine. Multiple LPARs running z/OS can form a Sysplex or Parallel Sysplex
IBM Parallel Sysplex
In computing, a Parallel Sysplex is a cluster of IBM mainframes acting together as a single system image with z/OS. Used for disaster recovery, Parallel Sysplex combines data sharing and parallel computing to allow a cluster of up to 32 systems to share a workload for high performance and high...
, whether on one machine or spread across multiple machines.
On IBM System P Power hardware
IBM Power Systems
Power Systems is the name of IBM's Power Architecture-based server line.Before the Power Systems line was announced on April 2, 2008, IBM had two distinct Power-based lines: the System i running IBM i - and the System p series running AIX or Linux.- History :IBM had two discrete Power Architecture...
, LPARs are managed by the Power Hypervisor. The Hypervisor or PowerVM
PowerVM
PowerVM, formerly known as Advanced Power Virtualization , is a chargeable feature of IBM POWER5, POWER6 and POWER7 servers and is required for support of micro-partitions and other advanced features...
acts as a virtual switch between the LPARs and also handles the virtual SCSI
SCSI
Small Computer System Interface is a set of standards for physically connecting and transferring data between computers and peripheral devices. The SCSI standards define commands, protocols, and electrical and optical interfaces. SCSI is most commonly used for hard disks and tape drives, but it...
traffic between LPARs. Micro-Partitioning
Micro-Partitioning
Micro-Partitioning is a form of logical partitioning which was introduced by IBM on systems using the POWER5 processor, and is also referred to as a shared processor partition, and only differs from a dedicated processor partition in the way CPU utilization is configured and managed by the POWER...
supports 10 times as many LPARs as processors with fractional allocations. It was introduced with the POWER5
POWER5
The POWER5 is a microprocessor developed and fabricated by IBM. It is an improved version of the highly successful POWER4. The principal improvements are support for simultaneous multithreading and an on-die memory controller...
processor. All IBM POWER5
POWER5
The POWER5 is a microprocessor developed and fabricated by IBM. It is an improved version of the highly successful POWER4. The principal improvements are support for simultaneous multithreading and an on-die memory controller...
and POWER6
POWER6
The POWER6 is a microprocessor developed by IBM that implemented the Power ISA v.2.03. When it became available in systems in 2007, it succeeded the POWER5+ as IBM's flagship Power microprocessor...
systems may be partitioned. Note that a full system partition may be defined where all resources are consumed by a single partition. System P servers with PowerVM enabled allow LPARs with shared CPUs to delegate their unused cycles into the shared pool. Dedicated processors are not available for sharing. Unused cycles become available for other partitions and are governed by the parameters specified when the LPAR is defined. Changes to a running partition can be made dynamically up to the maximum value set, and down to the minimum value set in the active profile. The changing of resource allocations without restart of the logical partition is called dynamic logical partitioning
Dynamic Logical Partitioning
Dynamic Logical Partitioning , is the capability of a logical partition to be reconfigured dynamically, without having to shut down the operating system that runs in the LPAR...
. IBM PowerVM
PowerVM
PowerVM, formerly known as Advanced Power Virtualization , is a chargeable feature of IBM POWER5, POWER6 and POWER7 servers and is required for support of micro-partitions and other advanced features...
(formerly known as Advanced POWER Virtualization or APV
APV
APV may refer to:* APV , or AP5, a selective NMDA receptor antagonist* Actuarial present value, a probability weighted present value often used in insurance* Adjusted present value, a variation of the net present value...
) is the licensed/purchased feature that enables the virtualization features on p4,5,6,7 series servers.
LPARs safely allow combining multiple test, development, quality assurance, and production work on the same server, offering advantages such as lower costs, faster deployment, and more convenience. IBM mainframe LPARs are Common Criteria EAL5 certifiable, equivalent to physically unconnected servers, so they support the highest security requirements, including military use. Nearly all IBM mainframes run with multiple LPARs with the IBM System z9 and IBM System z10
IBM System z10
IBM System z10 is a line of IBM mainframes. The z10 Enterprise Class was announced on February 26, 2008. On October 21, 2008, IBM announced the z10 Business Class , a scaled down version of the z10 EC...
supporting up to 60 LPARs.
See also
- VM (operating system)VM (operating system)VM refers to a family of IBM virtual machine operating systems used on IBM mainframes System/370, System/390, zSeries, System z and compatible systems, including the Hercules emulator for personal computers. The first version, released in 1972, was VM/370, or officially Virtual Machine Facility/370...
- Full virtualizationFull virtualizationIn computer science, full virtualization is a virtualization technique used to provide a certain kind of virtual machine environment, namely, one that is a complete simulation of the underlying hardware...
- Dynamic Logical PartitioningDynamic Logical PartitioningDynamic Logical Partitioning , is the capability of a logical partition to be reconfigured dynamically, without having to shut down the operating system that runs in the LPAR...
(DLPAR) - Workload PartitionsWorkload PartitionsAIX Workload partitions are a software implementation of operating system-level virtualization technology introduced in the IBM's AIX 6.1 operating system that provides application environment isolation and resource control....
(WPAR) - HiperSocketHiperSocketHiperSockets is an IBM technology for high-speed communications between partitions on a server with a hypervisor. The term is most commonly associated with zSeries, System z9 and System z10 mainframes which can provide in-memory TCP/IP connections between and among LPARs running several different...
, HypervisorHypervisorIn computing, a hypervisor, also called virtual machine manager , is one of many hardware virtualization techniques that allow multiple operating systems, termed guests, to run concurrently on a host computer. It is so named because it is conceptually one level higher than a supervisory program... - Virtualization
- PowerVMPowerVMPowerVM, formerly known as Advanced Power Virtualization , is a chargeable feature of IBM POWER5, POWER6 and POWER7 servers and is required for support of micro-partitions and other advanced features...
- FujitsuFujitsuis a Japanese multinational information technology equipment and services company headquartered in Tokyo, Japan. It is the world's third-largest IT services provider measured by revenues....
XPAR - SunSun MicrosystemsSun Microsystems, Inc. was a company that sold :computers, computer components, :computer software, and :information technology services. Sun was founded on February 24, 1982...
Solaris ContainersSolaris ContainersSolaris Containers is an implementation of operating system-level virtualization technology for x86 and SPARC systems, first released publicly in February 2004 in build 51 beta of Solaris 10, and subsequently in the first full release of Solaris 10, 2005.It is present in newer OpenSolaris based... - SunSun MicrosystemsSun Microsystems, Inc. was a company that sold :computers, computer components, :computer software, and :information technology services. Sun was founded on February 24, 1982...
LDOMLogical DomainsLogical 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...
External links
- Security on the Mainframe, December 2009, by Karan Singh, Chapter 4. Virtualization, page 24 and page 83.
- System i and System p: Logical Partitioning Guide
- IBM System p Virtualization — The most complete virtualization offering for UNIX and Linux