Just make sure that if you have a standalone CPC with CFs for that purpose that its engines are as fast as your other CPCs engines. I got into a performance problem 15 years ago when a 9674 was kept around longer that it should have been. You are only as fast as your slowest <insert appropriate component here>.
Bob -----Original Message----- From: IBM Mainframe Discussion List [mailto:IBM-MAIN@LISTSERV.UA.EDU] On Behalf Of R.S. Sent: Wednesday, July 11, 2018 5:25 AM To: IBM-MAIN@LISTSERV.UA.EDU Subject: Re: Sysplex between two hardware Maybe it's illusory, but that is in David Raften document. Obviously it's cheaper to have 2 CPCs than 3, but it is also cheaper to have 1 CPC than 2. The white paper clearly describes some structures as demanding duplexing or third CPC with failure-isolated CF. -- Radoslaw Skorupka Lodz, Poland W dniu 2018-07-11 o 01:15, Jesse 1 Robinson pisze: > It's easy to diss a solution as 'budget' when it saves someone *else* money. > The notion that a third CEC for standalone CF is substantially better than > ICF is illusory. If you truly believe that one extra CEC is necessary, then > you really need two extra CECs for CF because there are times when you have > to take one of them down. Maybe for repair, maybe for upgrade. So you still > need a backup. > > OTOH, 'logical standalone'--interesting term--with an ICF in each z/OS CEC is > a sufficient solution. We've run this way for years and survived two separate > hard-down CEC failures with zero recovery agony. My recommendation is to run > two CECs, one substantial box to run application hosts, and a minimal > 'penalty box' just for ICFs plus a few high-cost products that bill > significantly less on a small CEC. With proper structure duplexing, you have > extraordinary redundancy at a reasonable cost. > > . > . > 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 R.S. > Sent: Tuesday, July 10, 2018 3:00 AM > To: IBM-MAIN@LISTSERV.UA.EDU > Subject: (External):Re: Sysplex between two hardware > > W dniu 2018-07-10 o 06:56, Timothy Sipples pisze: >> I should also respond to this part: >> >> Radoslaw Skorupka wrote: >>> ...for availability reasons one should avoid having CF and z/OS LPAR >>> on the same hardware, which means.... >> That's not phrased as IBM would phase it, and it's not correct as written. >> >> Even when there's some merit in physically separating the CF, the >> physical separation need only be between that CF and the particular >> z/OS Parallel Sysplex it serves. Having other z/OS LPARs, even LPARs >> that are participating in other Parallel Sysplexes, on the same >> machine as the CF is consistent with IBM's recommendations here. >> >> David Raften has published a whitepaper (updated in May, 2018) that >> explains the various CF configuration options. The direct link to the >> current edition is here: >> >> https://public.dhe.ibm.com/common/ssi/ecm/zs/en/zsw01971usen/zsw01971u >> sen-.pdf > [...] > > I quickly browsed the document and found confirmation what I learned several > years ago. > That means: > Yes, you need either standalone CF (*see note) or CF structure duplexing! > This is required for *some* structures, but ...it is. David Rften call it > structures which /require failure independence/. > > Note: Standalone CF should be understood here as LOGICAL stand alone CF. > IBM-MIAN do not allo pictures, so I'll try to describe it: > SYSPLEX PROD: > z/OS 1 in CPC A, z/OS 2 in CPC B, and CF2 in CPC B or A. And CF1 in CPC C. > Three CPCs. > However CPC C may be used for other purpose, i.e. for test LPARs. > Anything but z/OS image belonging to the sysplex PROD. > > There is also two-CPC configuration > z/OS 1 + CF1 in CPC A, z/OS 2 + CF2 in CPC B and *some structures are > duplexed*. > What I heard unofficially from IBM-ers is such configuration is "budget" > read: when you cannot afford good one. > And the link between CFs should be really local (short). > > > Note2: it is also possible to build a configuration without dedicated > (logical stand alone) CF and without duplexing. Your choice. > However it is NOT resistant to all possible (single) failures. Yes, it > is still better than parallel sysplex with single CF, but still > vulnerable to some failures. > ====================================================================== -- Treść tej wiadomości może zawierać informacje prawnie chronione Banku przeznaczone wyłącznie do użytku służbowego adresata. 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