Logical partition: Difference between revisions

Revision as of 18:53, 22 May 2022

Revision as of 06:59, 22 August 2022

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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 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 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.

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On IBM mainframes, LPARs are managed by the [[PR/SM]] facility or a related, optional, simplified facility called Dynamic Partition Manager (DPM). All 64-bit IBM mainframes, except for the first generation 64-bit models (z900 and z800), 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 [[IBM Parallel Sysplex|Parallel Sysplex]], whether on one machine or spread across multiple machines.<ref name="redbooks.ibm.com">{{cite web |url=http://www.redbooks.ibm.com/abstracts/sg247803.html |title=Security on the Mainframe |date=2009-12-02 |access-date=2010-01-14 |first=Karan |last=Singh}}</ref>

On IBM [[IBM pSeries|System p]] [[IBM Power Systems|POWER hardware]], LPARs are managed by PHYP (the POWER [[Hypervisor#Unix and Linux servers|Hypervisor]]).<ref>{{cite web |url=http://www.ibm.com/support/knowledgecenter/POWER6/iphb2/iphb2hypervisor.htm |title=ArchivedIBM copyKnowledge Center |website=www.ibm.com |access-date=22 May 2022 |archive-url=https://web.archive.org/web/20161017172011/http://www.ibm.com/support/knowledgecenter/POWER6/iphb2/iphb2hypervisor.htm |archive-date=17 October 2016 |url-status=dead}}</ref> PHYP 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]], [[POWER6]], and successor 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]]. IBM PowerVM is the licensed/purchased feature that enables the virtualization features on p4, 5, 6, 7, and subsequent series servers.<ref>{{cite web |url=http://www-01.ibm.com/common/ssi/cgi-bin/ssialias?infotype=an&subtype=ca&appname=Demo&htmlfid=897/ENUS207-269 |title=IBM System p Virtualization — The most complete virtualization offering for UNIX and Linux |date=2007-11-06 |access-date=2010-04-06 |publisher=[[IBM]]}}</ref>

Exploiting [[Intel vPro]] (i.e. [[Non-uniform memory access]]), there are also implementations of Logical Partitioning based on [[Xeon#Haswell-based Xeon|Intel Xeon]] e.g. by [[Hitachi Data Systems]].<ref name="HDS">{{cite web |url=https://www.hds.com/en-us/pdf/white-paper/hitachi-white-paper-high-performance-nested-virtualization-with-hitachi-lpar.pdf |title=High-Performance Nested Virtualization With Hitachi Logical Partitioning Feature |date=2014-09-01 |access-date=2016-05-29 }}{{Dead link|date=March 2020 |bot=InternetArchiveBot |fix-attempted=yes }}</ref>