My recollection is that the term 'GDPS' was coined at a time when IBM had the *ambition* to run a single sysplex with members at a considerable distance apart. That ambition was too optimistic for the technology of the day, so 'GDPS' was redefined. A remnant of that shift is the difficulty of finding an actual spelling out of the acronym in GDPS doc.
GDPS as presented to my shop around Y2K had morphed into a service offering (not a 'product') for managing a sysplex and simplifying recovery of it elsewhere. That's how we use it. Whatever the supporting technology, DASD mirroring is key to GDPS. We actually implemented mirroring (XRC) before we obtained GDPS, which greatly simplified our previously RYO procedures. I've asked this question earlier in this thread. If you have a truly 'dispersed' sysplex with XCF functioning properly over a great distance, how do you survive the total loss of one glass house? At any given time, all members of the sysplex must be using one copy of DASD or another. As long as all remains sweetness and light, it doesn't much matter where the active copy resides and where the mirrored copy. But loss of one side implies that only one copy of the DASD remains accessible. How do the surviving sysplex members continue running seamlessly when the DASD farm suddenly changes? Of course you can re-IPL the surviving members and carry on. But that's basically what we do with 'cold' members. What is the advantage of running hot sysplex members in the remote site? . . 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 [email protected] -----Original Message----- From: IBM Mainframe Discussion List [mailto:[email protected]] On Behalf Of Peter Hunkeler Sent: Monday, January 15, 2018 11:49 PM To: [email protected] Subject: (External):AW: Re: SYSPLEX distance > I'm still not clear on how a 'geographically dispersed sysplex' (original > definition, not 'GDPS') would work. You say "original definition". I seem to remember, but might be wrong, that the term GDPS was coined when sysplexes were al contained within a single building or in buildings near by. GDPS was taking sysplexes with members in data centers up to a few kilometers apart. Apart from the longer distance between members, they were sysplexes as usual. No XRC involved. --Peter Hunkeler ---------------------------------------------------------------------- For IBM-MAIN subscribe / signoff / archive access instructions, send email to [email protected] with the message: INFO IBM-MAIN
