I'm somewhat puzzled by this thread. Could mean that I'm missing a basic point. We've been doing parallel sysplex since the mid-90s and therefore gone through a number of advances in technology. So let me toddle a ways down Memory Lane.
In the beginning, there was no duplexing. IBM promised it early but ran into technical difficulties and advised customers not to use it. Meanwhile the DB2 folks couldn't/didn't want to wait and so invented their own duplexing, but of course it worked only for DB2. Eventually IBM got 'system managed duplexing' (as opposed to application [DB2] duplexing) working and gave the green light. In order to enable system managed duplexing, you have to format the CFRM couple data set with "ITEM NAME(SMDUPLEX) NUMBER(1)". Once that's done, duplexing will be IN EFFECT for any supported structure whose policy definition allows it. Without duplexing in effect, a backup structure may take over but it may not be entirely in sync with the lost one. We have formatted CFRM couple data set with both SMREBLD and SMDUPLEX. They are not mutually exclusive. The effect is that for all structures allowed by policy, two structures are maintained in sync with each other. If either one fails, the other takes over automatically. On two widely separate occasions we lost an entire CEC containing duplexed ICFs. In both cases, once the CEC was repaired, the sysplex was reIPLed with no data loss. That transparent recovery is worth more than any performance degradation that duplexing might entail. . . J.O.Skip Robinson Southern California Edison Company Electric Dragon Team Paddler SHARE MVS Program Co-Manager 323-715-0595 Mobile 626-543-6132 Office ⇐=== NEW robin...@sce.com -----Original Message----- From: IBM Mainframe Discussion List [mailto:IBM-MAIN@LISTSERV.UA.EDU] On Behalf Of Allan Staller Sent: Tuesday, December 18, 2018 10:50 AM To: IBM-MAIN@LISTSERV.UA.EDU Subject: (External):Re: CFCC Performance Mike, Are you using Structure Duplexing and/or System managed rebuild? Al -----Original Message----- From: IBM Mainframe Discussion List <IBM-MAIN@LISTSERV.UA.EDU> On Behalf Of Mike Schwab Sent: Tuesday, December 18, 2018 12:23 PM To: IBM-MAIN@LISTSERV.UA.EDU Subject: Re: CFCC Performance We had 4 CFs. Two for the TestPlex and two for the Production Plex. On Tue, Dec 18, 2018 at 10:37 AM Allan Staller <allan.stal...@hcl.com> wrote: > > I am in the process or reconfiguring from a Single CF to multiple CFs (per > partition) to eliminate the single point of failure. > The subject of CFCC Thin Interrupts has been evaluated and will most likely > be implemented. > > As part of this process the discussion of DUPLEX CF structure vs. use of > SYSTEM MANAGED Rebuild has also come up. > > I have heard the use of duplexing has been deprecated in favor of system > managed rebuild for performance reasons. > CFCC Thin Interrupts might offset some of the (alleged) performance penalty. > > Can anyone point me to any documentation or contacts on the subject? > Searches if IBM Techdocs, Redbooks, ResourceLink, etc. have produced very > limited information. Most of which seem to be leaning in the SYSTEM MANAGED > Rebuild direction. ---------------------------------------------------------------------- For IBM-MAIN subscribe / signoff / archive access instructions, send email to lists...@listserv.ua.edu with the message: INFO IBM-MAIN
