The references I cited in my previous post are documentation elaborations. Nothing more, nothing less. IBM did not (generally) recommend multiple JES3 globals in a single Sysplex (which can consist of a single LPAR or not), past tense, and IBM does not (generally) recommend multiple JES3 globals in such an environment, present tense. Here's the previous documentation language, even before elaboration:
"Although it is possible to have multiple JES3 complexes within a Sysplex, IBM recommends a one-to-one relationship between the JES3 complex and the Sysplex...." Here's the revised language: "IBM recommends a one-to-one relationship between the JES3 complex and the Sysplex for ease of operations. If you do need to set up multiple global systems within the same Sysplex, the following considerations apply...." Though I prefer the revised language, the recommendation hasn't changed. A recommendation is not a requirement and never was, and a recommendation is certainly not a technology limitation. One ought to assign meaning and significance to every word, at least as a starting point. Especially when the recommendation was preceded by the words "it is possible." I'm not sure why the previous language (apparently, by some) was misread and misinterpreted. It certainly shouldn't have been. The previous language was perfectly clear. Nonetheless, IBM elaborated. This not exactly new recommendation (not requirement) is cause for celebration, one would think. Note that IBM recommended (and recommends) to clients they not follow this general JES3 recommendation when specifying the requirements for certain service offerings, as an example. Let's take a brief look at this "not exactly new" history. I can fairly easily trace JES3 back a quarter century. (Perhaps somebody else would like to go back into the pre-Sysplex JES3 era, from 1973 to 1990, to see what IBM recommended and/or required.) Sysplex debuted in 1990 with MVS/ESA Version 4. As IBM announcement letter 290-487 helpfully explains, JES3 took advantage of Sysplex from the start. I don't have convenient access to the MVS/ESA Version 4 documentation at the moment, but nearly 20 years ago IBM published this redbook, in the MVS/ESA Version 5 era: http://www.redbooks.ibm.com/redbooks/pdfs/sg244582.pdf Section 8.12 reiterates exactly the same JES3 recommendation...and then proceeds to provide instructions on how to violate IBM's recommendation. :-) There's even a diagram of that multiple global (and local) scenario, Figure 55. A quarter century is a long time to keep holding onto a ~41 year old IT grudge. :-) -------------------------------------------------------------------------------------------------------- Timothy Sipples IT Architect Executive, Industry Solutions, IBM z Systems, AP/GCG/MEA E-Mail: [email protected] ---------------------------------------------------------------------- For IBM-MAIN subscribe / signoff / archive access instructions, send email to [email protected] with the message: INFO IBM-MAIN
