IBM Parallel Sysplex: Difference between revisions

Revision as of 08:36, 7 September 2020

Revision as of 20:47, 29 January 2021

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* High speed, high quality, redundant cabling;

* Software ([[operating system]] services and, usually, [[middleware]] such as [[IBM DB2|DB2]]).

The Coupling Facility may be either a dedicated external system (a small mainframe, such as a [[System z9]] BC, specially configured with only coupling facility processors) or integral processors on the mainframes themselves configured as ICFs (Internal Coupling Facilities).<ref>{{cite web |url=https://www.pcmag.com/encyclopedia_term/0,2542,t=Coupling+Facility&i=40413,00.asp |title=Coupling Facility Definition |publisher=PC Magazine.com |accessdateaccess-date=April 13, 2009 }}</ref> It is recommended that at least one external CF be used in a parallel sysplex.<ref>{{cite web |url=http://www-ti.informatik.uni-tuebingen.de/os390/sysplex/sysplex/couplfac.pdf |title=Coupling Facility |accessdateaccess-date=April 13, 2009 }}</ref> It is recommended that a Parallel Sysplex has at least two CFs and/or ICFs for redundancy, especially in a production data sharing environment. Server Time Protocol (STP) replaced the Sysplex Timers beginning in 2005 for System z mainframe models z990 and newer.<ref>{{cite web |title=Migrate from a Sysplex Timer to STP |url=http://publib.boulder.ibm.com/infocenter/zos/v1r9/index.jsp?topic=/com.ibm.zos.r9.e0zm100/sttostp.htm |publisher=IBM |accessdateaccess-date=April 15, 2009 }}</ref> A Sysplex Timer is a physically separate piece of hardware from the mainframe,<ref>{{cite web |title=Sysplex Timer |url=http://www.symmetricom.com/resources/compliance-certifications/sysplex-timer/ |publisher=Symmetricom |accessdateaccess-date=April 15, 2009 }}</ref> whereas STP is an integral facility within the mainframe's microcode.<ref>{{cite web |title=IBM Server Time Protocol (STP) |url=http://www-03.ibm.com/systems/z/advantages/pso/stp.html |publisher=IBM |accessdateaccess-date=April 15, 2009 }}</ref>

With STP and ICFs it is possible to construct a complete Parallel Sysplex installation with two connected mainframes. Moreover, a single mainframe can contain the internal equivalent of a complete physical Parallel Sysplex, useful for application testing and development purposes.<ref>{{cite web |url=http://www.zjournal.com/index.cfm?section=article&aid=308 |title=MVS Boot Camp: IBM Health Checker |first=John E. |last=Johnson |publisher=z/Journal |accessdateaccess-date=April 15, 2009 }}{{dead link|date=January 2018 |bot=InternetArchiveBot |fix-attempted=yes }}</ref>

The IBM Systems Journal dedicated a full issue to all the technology components.<ref>{{cite web |url=http://researchweb.watson.ibm.com/journal/sj36-2.html |title=IBM's System Journal on S/390 Parallel Sysplex Clusters |accessdateaccess-date=24 April 2017 }}</ref>

==Server Time Protocol==

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==Geographically Dispersed Parallel Sysplex==

{{redirect|GDPS|other uses|GDPS (disambiguation)}}

'''Geographically Dispersed Parallel Sysplex''' ('''GDPS''') is an extension of Parallel Sysplex of mainframes located, potentially, in different cities. GDPS includes configurations for single site or multiple site configurations:<ref>{{cite conference |first=Riaz |last=Ahmad |date=March 5, 2009 |title=GDPS 3.6 Update & Implementation |publisher=SHARE |___location=Austin, TX |url=http://ew.share.org/proceedingmod/abstract.cfm?abstract_id=19145 |accessdateaccess-date=April 17, 2009 }}{{Dead link|date=January 2020 |bot=InternetArchiveBot |fix-attempted=yes }}</ref>

* GDPS HyperSwap Manager: This is based on synchronous [[Peer to Peer Remote Copy]] (PPRC) technology for use within a single data center. Data is copied from the primary storage device to a secondary storage device. In the event of a failure on the primary storage device, the system automatically makes the secondary storage device the primary, usually without disrupting running applications.

* GDPS Metro: This is based on synchronous data mirroring technology (PPRC) that can be used on mainframes {{convert|200|km|mi}} apart. In a two-system model, both sites can be administered as if they were one system. In the event of a failure of a system or storage device, recovery can occur automatically, with limited or no data loss.