Eric, IIRC from my last company, we had redundancy across two CECs using CICS and DB2 data sharing. It was configured in such a way as to be able to take a hit on one CEC and keep on trucking. We provided multiple, identical, concurrently operating CICS regions and DB2 subsystems to which CICS automatically and dynamically routed transactions. When one or more CICS regions became unavailable, due to maintenance or application/transaction error, other CICS regions and DB2 subsystems were available to process the work.
Once that was running correctly, we implemented GDPS, replicating the setup to a secondary datacenter. Bob -----Original Message----- From: IBM Mainframe Discussion List [mailto:[email protected]] On Behalf Of Barbara Nitz Sent: Wednesday, September 09, 2009 3:59 AM To: [email protected] Subject: Re: Sysplex Basic Question Eric, >Can you set up a sysplex so that both machines have everything running on >each CPU in the plex, and when one system crashes the other will >automatically take over everything? In theory: Yes. With the exception of the running transaction. That one will get terminated. I said 'in theory', because *I* have never seen a sysplex set up like that. I guess one needs to look at the big GDPS installations to find it. I will not comment on CICS specifically (no experience here whatsoever), though. > Say you have SYSA and SYSB. Each has >10 CICS regions running. Half of the applications are routed to SYSA, and >the other half to SYSB, but all 10 CICS regions are running on each system. >If SYSA crashes, can all transactions now be routed to SYSB? I'm sure that >any transactions on SYSA at the time of the crash will not finish, and have >to be reentered, but I was under the impression that everything after the >crash could then be routed to SYSB after the SYSA crash. I'm not sure if >that could be done automatically by automation, or would take someone to >look at it and type in a command. Again in theory, given the proper setup, yes, all transactions get automagically routed to the other system, without operator (manual) intervention. It is my understanding that it is hugely expensive to be set up like that. Just staying with the basic things for sysplex (and the list is incomplete): You will need true failure independence for the couple CDSs (meaning they really have to be behind two different control units - expensive). Your CF structures better be in duplexing state (which implies direct extra connections between just the CFs - expensive) for either CFs on different boxes or CFs that are standalone boxes - expensive. Your applications will need to be written in such a way that data sharing is still performing to your business needs. *We* cannot use IMS shared q (which would be a prereq for that scenario) because performacne is so bad. And that is just naming a few things. Best regards, Barbara ---------------------------------------------------------------------- For IBM-MAIN subscribe / signoff / archive access instructions, send email to [email protected] with the message: GET IBM-MAIN INFO Search the archives at http://bama.ua.edu/archives/ibm-main.html
