Logical partition: Difference between revisions

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{{in use}}

{{hatnote|[[Dynamic Partition Manager]] redirects here}}

{{for|the type of disk partition|Disk partitioning#Extended partition}}

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{{Short description|Subset of a computer's hardware resources, virtualized as a separate computer}}

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A '''logical partition''' ('''LPAR''') is a subset of a computer's hardware resources, [[Platform virtualization|virtualized]] as a separate computer. In effect, a physical machine can be partitioned into multiple logical partitions, each hosting a separate instance of an [[operating system]].<ref name="Singh">{{cite web |url=http://www.redbooks.ibm.com/redpieces/pdfs/sg247803.pdf |title=Security on the Mainframe |date=2009-12-02 |access-date=2010-04-06 |first=Karan |last=Singh |url-status=dead |archive-url=https://web.archive.org/web/20110617113238/http://www.redbooks.ibm.com/redpieces/pdfs/sg247803.pdf |archive-date=2011-06-17 }}</ref>

==PR/SM History ==

{{section rewrite|date=December 2024}}

Although the terms ''PR/SM'' and ''LPAR'' are often used interchangeably in IBM Z, including in IBM documentation, ''PR/SM'' was not present in the [[IBM 370/168]]'s [[VM (operating system)|Virtual Machine Facility/370]]; it came in with the [[IBM 3090]], years later. Formally, LPAR designates the logical partitioning function and mode of operation, whereas PR/SM is the commercial designation of the feature.<ref name="Singh"/>{{rp|83}}

[[IBM]] developed the concept of [[hypervisor]]s ([[virtual machine]]s in [[IBM CP-40|CP-40]] and [[CP-67]]) and in 1972 provided it for the [[IBM System/370|S/370]] as [[VM (operating system)|Virtual Machine Facility/370]].<ref>{{

cite book |url=http://www.vm.ibm.com/pubs/HCSF8A50.PDF |title=z/VMbuilt on IBM Virtualization Technology General Information Version 4 Release 3.0 |id=GC24-5991-04 |date=2002-04-12 |publisher=[[IBM]]}}</ref> IBM introduced the Start Interpretive Execution (SIE) instruction (designed specifically for the execution of virtual machines) in 1983 as part of [[IBM System/370-XA|370-XA]] architecture on the [[IBM 3081]], as well as VM/XA versions of VM to exploit it.

[[Amdahl Corporation]]'s Multiple Domain Facility (MDF) was introduced in 1982.<ref>{{cite journal |last1=Doran |first1=R.W. |title=Amdahl multiple-___domain architecture |journal=Computer |date=October 1988 |volume=21 |issue=10 |pages=20–28 |doi=10.1109/2.7054 |s2cid=1738798 |url=http://www-ti.informatik.uni-tuebingen.de/~spruth/edumirror/xx067.pdf |archive-url=https://web.archive.org/web/20170829211626/http://www-ti.informatik.uni-tuebingen.de/~spruth/edumirror/xx067.pdf |archive-date=2017-08-29}}</ref> IBM began marketingintroduced its functionally similar PR/SM in 1988, implemented on its [[ESA/390370]] architecture released that year. MDF-basedwith LPARthe technology[[IBM continued3090]] toprocessors.<ref>{{cite beweb|url=http://www.redbooks.ibm.com/redpapers/pdfs/redp5157.pdf|title=IBM developedZ separatelyFunctional byMatrix|author1=Frank Amdahl,Packheiser|author2=Octavian andLascu|author3=Bill White|page=18|publisher=[[Hitachi Data SystemsIBM]]|date=2018}}</ref> inPR/SM part(Processor forResource/System theirManager) implementationsis ofa thetype-1 new[[Hypervisor]] architecture, which featured the introduction of(a [[accessvirtual registersmachine]] monitor) that allowedallows usemultiple oflogical multiplepartitions to share physical resources such as [[dataCentral spaceprocessing unit|CPU]]s, addressable by a singlememory, [[addressChannel spaceI/O|I/O channels]]. IBMand subsequentlyLAN continuedinterfaces; itsthe LPARLPARs developmentcan withshare itsI/O 64-bitdevices [[Systemsuch z]] andas [[IBMdirect AS/400access storage device]]s architectures(DASD). LPARInitially, the operator could select either basic mode or logical partition mode. and PR/SM reconfigurationsis canintegrated bewith madeall without[[IBM rebootingSystem the computer,z]] i.emachines. Formally, whileLPAR somedesignates LPARsthe remainmode active.of Reconfigurationsoperation canor includean changingindividual channellogical pathpartition, definitionswhereas andPR/SM deviceis definitionsthe commercial designation of the feature.<ref name="Singh"/>{{rp|83}}

{{Short description|IBM mainframe hypervisor}}

{{primary sources|date = February 2009}}

MDF-based LPAR technology continued to be developed separately by Amdahl, and [[Hitachi Data Systems]] in part for their implementations of the new ESA/370 architecture, which featured the introduction of [[access registers]] that allowed use of multiple [[data space]]s addressable by a single [[address space]].

In mainframe computing '''PR/SM''' ('''Processor Resource/System Manager''') is a type-1 [[Hypervisor]] (a [[virtual machine]] monitor) that allows multiple [[LPAR|logical partition]]s to share physical resources such as [[Central processing unit|CPU]]s, [[Channel I/O|I/O channels]] and LAN interfaces; when sharing channels, the LPARs can share I/O devices such as [[direct access storage device]]s (DASD). PR/SM is integrated with all [[IBM System z]] machines. Similar facilities exist on the [[IBM Power Systems]] family, and its predecessors.

IBM subsequently continued its LPAR development with its 64-bit [[System z]] architecture. 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.

[[IBM]] introduced PR/SM in 1988 with the [[IBM 3090]] processors.<ref>{{cite web|url=http://www.redbooks.ibm.com/redpapers/pdfs/redp5157.pdf|title=IBM Z Functional Matrix|author1=Frank Packheiser|author2=Octavian Lascu|author3=Bill White|page=18|publisher=[[IBM]]|date=2018}}</ref>

IBM developed the concept of hypervisors in their [[IBM CP-40|CP-40]] and [[CP-67]], and in 1972 provided it for the [[IBM System/370|S/370]] as Virtual Machine Facility/370.<ref>{{cite manual |url=http://www.vm.ibm.com/pubs/HCSF8A50.PDF |title=z/VM built on IBM Virtualization Technology General Information Version 4 Release 3.0 |id=GC24-5991-04 |date=April 2002 |publisher=IBM}}</ref> IBM introduced the Start Interpretive Execution ('''SIE''') instruction as part of 370-XA on the 3081, and VM/XA versions of [[VM (operating system)|VM]] to exploit it. PR/SM is a type-1 Hypervisor based on the CP component of [[VM (operating system)|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 Z]] and [[IBM LinuxONE]] machines.

IBM introduced a related, simplified, optional feature called [[Dynamic Partition Manager]] (DPM) on its IBM z13 and first generation IBM LinuxONE machines. DPM provides Web-based user interfaces for many LPAR-related configuration and monitoring tasks.

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.

== External links ==

* {{cite web

|url = http://publib.boulder.ibm.com/infocenter/eserver/v1r2/index.jsp?topic=/eicaz/eicazzlpar.htm

|title = System z PR/SM

|url-status = dead

|archiveurl = https://archive.today/20130103052157/http://publib.boulder.ibm.com/infocenter/eserver/v1r2/index.jsp?topic=/eicaz/eicazzlpar.htm

|archivedate = 2013-01-03}}

IBM later introduced LPARs to their [[IBMPowerPC]]-based i|iSeries[[AS/400]] (later called iSeries) and [[IBM pSeries|pSeries]] servers in 1999 and 2001, respectively,<ref>{{cite web |url=http://www.ibm.com/developerworks/aix/library/au-aix-vioserver-v2/index.html |title=POWER5 Virtualization: How to set up the Virtual I/O Server |access-date=2008-09-September 25, 2008 |date=2005-06-June 29, 2005 |first=Nigel |last=Griffiths |website=[[IBM]] |url-status=dead |archive-url=https://web.archive.org/web/20080611131520/http://www.ibm.com/developerworks/aix/library/au-aix-vioserver-v2/index.html |archive-date=2008-06-11 }}</ref> albeit with varying technical specifications. Multiple operatingThose systems areuse compatiblePHYP with(the LPARs,POWER includingHypervisor) [[z/OS]],to [[z/VM]],enable [[z/VSE]],their [[z/TPF]],LPAR [[AIXfunctionalities operatingsince system|AIX]],approximately [[Linux]],2000 andin [[IBMPOWER4 i]]systems. This Insupport continues in [[diskIBM array|storagePower systemsSystems]], such as the IBM TotalStorage DS8000, LPARs allow for multiple virtual instances of a storage array to exist within a single physical array.

==References==

{{Reflist}}

{{Virtualization products}}

{{DEFAULTSORT:PR SM}}

[[Category:Virtualization software]]

[[Category:IBM mainframe technology]]

{{software-stub}}

{{mainframe-compu-stub}}

==History==

IBM developed the concept of [[hypervisor]]s ([[virtual machine]]s in [[IBM CP-40|CP-40]] and [[CP-67]]) and in 1972 provided it for the [[IBM System/370|S/370]] as [[VM (operating system)|Virtual Machine Facility/370]].<ref>{{

cite book |url=http://www.vm.ibm.com/pubs/HCSF8A50.PDF |title=z/VMbuilt on IBM Virtualization Technology General Information Version 4 Release 3.0

|id=GC24-5991-04 |date=2002-04-12 |publisher=[[IBM]]}}</ref> IBM introduced the Start Interpretive Execution (SIE) instruction (designed specifically for the execution of virtual machines) as part of 370-XA architecture on the 3081, as well as 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 LPARs to share physical resources. It is a standard feature on [[IBM System z]] only. An IBM POWER system uses PHYP (the POWER Hypervisor) to enable its LPAR functionalities for System p and System i since approximately 2000 in POWER4 systems.

[[Amdahl Corporation]]'s Multiple Domain Facility (MDF) was introduced in 1982.<ref>{{cite journal |last1=Doran |first1=R.W. |title=Amdahl multiple-___domain architecture |journal=Computer |date=October 1988 |volume=21 |issue=10 |pages=20–28 |doi=10.1109/2.7054 |s2cid=1738798 |url=http://www-ti.informatik.uni-tuebingen.de/~spruth/edumirror/xx067.pdf |archive-url=https://web.archive.org/web/20170829211626/http://www-ti.informatik.uni-tuebingen.de/~spruth/edumirror/xx067.pdf |archive-date=2017-08-29}}</ref> IBM began marketing its functionally similar PR/SM in 1988, implemented on its [[ESA/390]] architecture released that year. MDF-based LPAR technology continued to be developed separately by Amdahl, and [[Hitachi Data Systems]] in part for their implementations of the new architecture, which featured the introduction of [[access registers]] that allowed use of multiple [[data space]]s addressable by a single [[address space]]. IBM subsequently continued its LPAR development with its 64-bit [[System z]] and [[IBM AS/400]] 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.

Multiple operating systems are compatible with LPARs, including [[z/OS]], [[z/VM]], [[z/VSE]], and [[z/TPF]] on mainframes, [[AIX operating system|AIX]] and [[IBM i]] on IBM Power Systems, and [[Linux]] on both.

IBM later introduced LPARs to their [[IBM i|iSeries]] and [[IBM pSeries|pSeries]] servers in 1999 and 2001, respectively,<ref>{{cite web |url=http://www.ibm.com/developerworks/aix/library/au-aix-vioserver-v2/index.html |title=POWER5 Virtualization: How to set up the Virtual I/O Server |access-date=2008-09-25 |date=2005-06-29 |first=Nigel |last=Griffiths |website=[[IBM]] |url-status=dead |archive-url=https://web.archive.org/web/20080611131520/http://www.ibm.com/developerworks/aix/library/au-aix-vioserver-v2/index.html |archive-date=2008-06-11 }}</ref> albeit with varying technical specifications. Multiple operating systems are compatible with LPARs, including [[z/OS]], [[z/VM]], [[z/VSE]], [[z/TPF]], [[AIX operating system|AIX]], [[Linux]], and [[IBM i]]. In [[disk array|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.

In [[disk array|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.

In first part of 2010 year, [[Fujitsu]] announced availability of its [[x86-64]] PRIMEQUEST line of servers,<ref>[http://www.fujitsu.com/global/news/pr/archives/month/2010/20100331-01.html Fujitsu Upgrades Lineup of PRIMEQUEST Mission-Critical Servers]</ref> which support LPARs.

In secondearly part2010 [[Fujitsu]] announced availability of 2011its year[[x86-64]] PRIMEQUEST line of servers,<ref>{{citation |url=http://www.fujitsu.com/global/news/pr/archives/month/2010/20100331-01.html |title=Fujitsu Upgrades Lineup of PRIMEQUEST Mission-Critical Servers}}</ref> which support LPARs. In late 2011, [[Hitachi]] has announced availability of CB2000 and CB320 blade systems,<ref>{{cite journalcitation | url=http://www.hitachi.com/rev/archive/2012/__icsFiles/afieldfile/2012/03/26/r2012_02_104.pdf | title=Logical Partitioning Feature of CB Series Xeon servers Suitable for Robust and Reliable Cloud | archive-url=https://web.archive.org/web/20120914083641/http://www.hitachi.com/rev/archive/2012/__icsFiles/afieldfile/2012/03/26/r2012_02_104.pdf | archive-date=2012-09-14 |author1=Hitoshi Ueno |author2=Shinichi Matsumura | journal=Hitachi Review |volume=61 |date=2012 |issue=2}}</ref> which support LPAR on [[x86-64]] hardware.

== Hardware partitioning ==

Logical partitioning divides hardware resources. Two LPARs may access [[memory (computers)|memory]] from a common memory chip, provided that the ranges of addresses directly accessible to each do not overlap. It is possible for one partition to control memory managed by a second partition indirectly by communicating with a process on the partition with direct access, which acts as an intermediary. [[CPU]]s may be dedicated to a single LPAR or shared. While on Amdahl's MDF (Multiple Domain Facility) it was possible to configure an LPAR with both shared and dedicated CPUs, this is no longer possible with any mainframes currently in the market.

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LPARs (with sufficient certification) 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 [[Evaluation Assurance Level#EAL5: Semiformally Designed and Tested|EAL 5+]] 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 and later models up to 85.<ref name="redbooks.ibm.com"/>

== See also ==

*[[VM (operating system)]]

*[[ {{anl|Dynamic Logical Partitioning]] (DLPAR)}}

*[[ {{anl|Full virtualization]]}}

*[[Dynamic Logical Partitioning]] (DLPAR)

* {{anl|HiperSocket}}

*[[Workload Partitions]] (WPAR)

* {{anl|Logical Domains}}

*[[HiperSocket]], [[Hypervisor]]

*[[ {{anl|Platform virtualization|Virtualization]]}}

*[[ {{anl|PowerVM]]}}

*[[Sun Microsystems{{anl|Sun]] [[Solaris Containers]]}}

*[[ {{anl|Workload Partitions]] (WPAR)}}

*[[Sun Microsystems|Sun]] [[Logical Domains|LDOM]]

==References==

{{Reflist}}

{{refs}}

==External links==

*[https://web.archive.org/web/20110617113238/http://www.redbooks.ibm.com/redpieces/pdfs/sg247803.pdf Security on the Mainframe], December 2009, by Karan Singh, Chapter 4. Virtualization, page 24 and page 83.

*[https://www-01.ibm.com/servers/resourcelink/lib03030.nsf/web+search/0E6125F89F8B8EF6852572E6007E884D/$file/sa76-0098.pdf System i and System p: Logical Partitioning Guide]{{dead link|date=January 2018 |bot=InternetArchiveBot |fix-attempted=yes }}

*[http://www-01.ibm.com/common/ssi/cgi-bin/ssialias?infotype=an&subtype=ca&appname=Demo&htmlfid=897/ENUS207-269 IBM System p Virtualization — The most complete virtualization offering for UNIX and Linux]

*[https://web.archive.org/web/20120304165859/http://www.hds.com/assets/pdf/hitachi-datasheet-compute-blade-logical-partitioning-lpar.pdf Hitachi Compute Blade LPARs]

*[http://www.fujitsu.com/downloads/PRMPWR/wp-xpar.pdf Fujitsu XPARs (SPARC)] and [http://www.fujitsu.com/global/services/computing/server/primequest/technology/io-partitioning.html "Flexible I/O and Partitioning" (x86_64)]

== External links ==

{{DEFAULTSORT:Lpar}}

* [https://web.archive.org/web/20110617113238/http://www.redbooks.ibm.com/redpieces/pdfs/sg247803.pdf Security on the Mainframe], December 2009, by Karan Singh, Chapter 4. Virtualization, page 24 and page 83.

* [https://techknowledgedb.com/system-i-and-system-p/ System i and System p: Logical Partitioning Guide]

* [httphttps://www-01.ibm.com/commondocs/ssien/cgi-binannouncements/ssialias?infotype=an&subtype=ca&appname=Demo&htmlfid=897archive/ENUS207-269 IBM System p Virtualization — The most complete virtualization offering for UNIX and Linux]

* [https://public.dhe.ibm.com/systems/power/docs/hw/p9/p9hat.pdf Power Systems Logical partitioning]

* [https://web.archive.org/web/20120304165859/http://www.hds.com/assets/pdf/hitachi-datasheet-compute-blade-logical-partitioning-lpar.pdf Hitachi Compute Blade LPARs]

* [http://www.fujitsu.com/downloads/PRMPWR/wp-xpar.pdf Fujitsu XPARs (SPARC)] and [http://www.fujitsu.com/global/services/computing/server/primequest/technology/io-partitioning.html "Flexible I/O and Partitioning" (x86_64)]

|url =* [http://publib.boulder.ibm.com/infocenter/eserver/v1r2/index.jsp?topic=/eicaz/eicazzlpar.htm System z PR/SM]

{{Virtualization products}}

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