# Micro-Partitioning

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**Micro-Partitioning**, also known as **shared processor partitioning**,[1] is a form of [logical partitioning](/source/Logical_partitioning) which was introduced by [IBM](/source/IBM) on systems using the [POWER5](/source/POWER5) processor. It only differs from a dedicated processor partition in the way CPU utilization is configured and managed by the [POWER Hypervisor](/source/POWER_Hypervisor) (PHYP) firmware.[2] All IBM [POWER5](/source/POWER5) and [POWER6](/source/POWER6) systems are partitioned and will run "on top" of the PHYP.[3]

The POWER Hypervisor controls time slicing, management of all hardware interrupts, dynamic movement of resources across multiple operating systems, and dispatching of logical partition workloads.

When a shared processor partition is activated by the PHYP, the [logical partition](/source/Logical_partition) (LPAR) is guaranteed a certain processing capacity, if needed, and a number of virtual processors, based on configuration and current availability. The processing capacity is drawn from a pool of shared processor resources.[4]: 6

The minimum processing capacity per processor is 1/10 of a physical processor core, with a further granularity of 1/100.[5][6][7] The PHYP uses a 10 ms time slicing dispatch window for scheduling all shared processor partitions' virtual processor queues to the PHYP physical processor core queues. A shared processor partition can be either *capped* or *uncapped*. A capped partition can never exceed the currently configured processing capacity, whereas an uncapped partition can exceed the currently configured processing capacity up to 100% of the number of the currently configured virtual processors.[4]: 10

If the shared processor partition is [DLPAR](/source/Dynamic_Logical_Partitioning) capable, the number of virtual processors and processing capacity can be altered dynamically for the partition.[4]: 9

## References

1. **[^](#cite_ref-1)** Chen, Whei-Jen; Jason Chan; Olaf Mueller; Malcolm Singh; Tapio Väättänen (2009). [*DB2 Virtualization*](https://www.google.com/books/edition/DB2_Virtualization/5U_AAgAAQBAJ?hl=en&gbpv=1&dq=%22shared+processor+partitioning%22&pg=PA49&printsec=frontcover). IBM Redbooks. p. 49. [ISBN](/source/ISBN_(identifier)) [9780738433431](https://en.wikipedia.org/wiki/Special:BookSources/9780738433431) – via Google Books.

1. **[^](#cite_ref-2)** Williams, David E. (2007). [*Virtualization with Xen*](https://www.google.com/books/edition/Virtualization_with_Xen_tm_Including_Xen/nquBOlkR9BsC?hl=en&gbpv=1&bsq=%22micro%20-%20partitioning%22). Elsevier. pp. 7–8. [ISBN](/source/ISBN_(identifier)) [9780080553931](https://en.wikipedia.org/wiki/Special:BookSources/9780080553931) – via Google Books.

1. **[^](#cite_ref-3)** Victor, Jeff; Jeff Savit; Gary Combs; Simon Hayler; Bob Netherton (2011). [*Oracle Solaris 10 System Virtualization Essentials*](https://archive.org/details/oraclesolaris10s0000unse/page/34/). Prentice-Hall. p. 34. [ISBN](/source/ISBN_(identifier)) [013708188X](https://en.wikipedia.org/wiki/Special:BookSources/013708188X) – via Google Books.

1. ^ [***a***](#cite_ref-gibson_4-0) [***b***](#cite_ref-gibson_4-1) [***c***](#cite_ref-gibson_4-2) Gibson, Chris (July 2007). ["Implementing Micro-Partitioning on the IBM p5 595 Server"](https://www.google.com/books/edition/Sys_Admin/CyFAAQAAIAAJ?hl=en&gbpv=1&bsq=%22Implementing+Micro-Partitioning+on+the+IBM%22&dq=%22Implementing+Micro-Partitioning+on+the+IBM%22&printsec=fr). *Sys Admin*. Vol. 16, no. 15. CMP Media. pp. 6–16 – via Google Books.

1. **[^](#cite_ref-5)** Mears, Jennifer (May 3, 2004). "IBM powers up server partitioning". *Network World*. Vol. 21, no. 18. IDG Publications. p. 8. [ProQuest](/source/ProQuest) [215966612](https://www.proquest.com/docview/215966612).

1. **[^](#cite_ref-6)** Langley, Nick (March 28, 2006). "AIX celebrates 20th anniversary and forges ahead alongside Linux". *Computer Weekly*. Reed Business Information. p. 50. [ProQuest](/source/ProQuest) [237027130](https://www.proquest.com/docview/237027130) – via ProQuest.

1. **[^](#cite_ref-7)** Akin, David (July 15, 2004). ["IBM to launch servers offering more power for a lot less cash"](https://www.proquest.com/docview/383844362/). *The Globe and Mail*. Bell Globemedia. p. B11 – via ProQuest.

## See also

- [VM (operating system)](/source/VM_(operating_system))

## External links

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

- [System i and System p: Introduction to Virtualization](https://www-01.ibm.com/servers/resourcelink/lib03030.nsf/pages/IntroductionToVirtualization/$file/sa76-0145.pdf)[*[permanent dead link](https://en.wikipedia.org/wiki/Wikipedia:Link_rot)*]

- [System i and System p: Advanced POWER Virtualization Operations Guide](https://www-01.ibm.com/servers/resourcelink/lib03030.nsf/pages/AdvancedPOWERVirtualizationOperationsGuide/$file/sa76-0100.pdf)[*[permanent dead link](https://en.wikipedia.org/wiki/Wikipedia:Link_rot)*]

- [System i and System p: Logical Partitioning Guide](https://www-01.ibm.com/servers/resourcelink/lib03030.nsf/web+search/0E6125F89F8B8EF6852572E6007E884D/$file/sa76-0098.pdf)[*[permanent dead link](https://en.wikipedia.org/wiki/Wikipedia:Link_rot)*]

- [Advanced POWER Virtualization on IBM System p5: Introduction and Configuration](http://www.redbooks.ibm.com/abstracts/sg247940.html)

- [IBM System p Advanced POWER Virtualization Best Practices](http://www.redbooks.ibm.com/abstracts/redp4194.html)

- [Partitioning Implementations for IBM eServer p5 Servers, SG24-7039](http://www.redbooks.ibm.com/abstracts/sg247039.html)

- [POWER5 Hypervisor](https://web.archive.org/web/20060908184316/http://www-941.ibm.com/collaboration/wiki/display/LinuxP/POWER5+Hypervisor)

- [Virtualization Concepts](https://web.archive.org/web/20060908185742/http://www-941.ibm.com/collaboration/wiki/display/LinuxP/Virtualization+Concepts)

- [Virtualization in System p](http://www.ibm.com/developerworks/aix/library/au-syspvirtualization/index.html)

- [POWER5 Hypervisor](https://web.archive.org/web/20061022012134/http://www-941.ibm.com/collaboration/wiki/display/virtualization/POWER5+Hypervisor?decorator=printable)

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Adapted from the Wikipedia article [Micro-Partitioning](https://en.wikipedia.org/wiki/Micro-Partitioning) by Wikipedia contributors ([contributor history](https://en.wikipedia.org/wiki/Micro-Partitioning?action=history)). Available under [Creative Commons Attribution-ShareAlike 4.0 International](https://creativecommons.org/licenses/by-sa/4.0/). Changes may have been made.