OK, I really did not understand the process. Site A mirrors to Site B. True production runs at Site B for some time. Then you want to mirror back to Site A with then current data resulting from ongoing production at Site B.
The answer is that you must entirely mirror *all* data from Site B back to Site A in order to get up to date. It's not just a matter of reversing direction. It's how XRC works (and I suspect also PPRC although I have no experience with it). In the case of XRC, data updates are sent continuously to the receiving site. If the receiving site goes temporarily unavailable via XRC SUSPEND, the sender is notified to keep track of updates in a bit map in each controller. When XRC is RESUMEd, the sender uses the bit map to 'refresh' the receiving site and bring his copy current. All of this depends entirely on the receiving site picking up exactly where he left off with absolutely nothing changed on his side during the interruption. All missing updates are applied--accumulated ones as well as ongoing updates--until both sites are back in synch. In the case in question, there is no SUSPEND/RESUME operation and no bit map. You have no choice but to do a full mirror to bring Site A in synch with Site B, which has the current data. The difference between full copy and resync is elapsed time and network traffic. . . JO.Skip Robinson Southern California Edison Company Electric Dragon Team Paddler SHARE MVS Program Co-Manager 626-302-7535 Office 323-715-0595 Mobile jo.skip.robin...@sce.com From: "Pommier, Rex R." <rex.pomm...@cnasurety.com> To: IBM-MAIN@LISTSERV.UA.EDU, Date: 06/06/2013 04:31 PM Subject: Re: XRC Volume Resync on a Return Home Sent by: IBM Mainframe Discussion List <IBM-MAIN@LISTSERV.UA.EDU> Ed brings up an interesting question. So with your response, you're saying that with PPRC, you cannot 'reverse' the mirror. Breaking and re-establishing the mirror pairs will require a full data re-push back to the now secondary site. Rex -----Original Message----- From: IBM Mainframe Discussion List [mailto:IBM-MAIN@LISTSERV.UA.EDU] On Behalf Of Mike Schwab Sent: Thursday, June 06, 2013 5:10 PM To: IBM-MAIN@LISTSERV.UA.EDU Subject: Re: XRC Volume Resync on a Return Home With PPRC, you would break the pairs and re-establish in the opposite direction. When are all replicated and almost up to date, shut down the primary, wait for updates to propate, and start at the secondary. XRC may be a bit different. On Thu, Jun 6, 2013 at 4:26 PM, VanBebber, Edmond@CIO <edmond.vanbeb...@state.ca.gov> wrote: > Thanks for the reply. I don't think that is the case when you say 'you cannot just return operations back to the original application region'. Banks do this all the time. They run production in site A for a few months then switch and run in site B for a few months. I'm not really asking if this can be done, I'm asking if you reverse replication with XRC, can you do an incremental resync without GDPS and configured for a region switch. > > -----Original Message----- > From: IBM Mainframe Discussion List [mailto:IBM-MAIN@LISTSERV.UA.EDU] On Behalf Of Skip Robinson > Sent: Thursday, June 06, 2013 2:09 PM > To: IBM-MAIN@LISTSERV.UA.EDU > Subject: Re: XRC Volume Resync on a Return Home > > If you are truly 'running production in a recovery site', then you cannot > just 'return operations back to the original application region'. I hate > to sound pedantic, but running production anywhere other than its home > location. means that the latest live, current production data now lives at > the recovery site. 'Home data' is now obsolete. You would have to restore > that data from the recovery site at home, overlaying the old data. > > If that's not what you mean, please clarify. > > . > . > JO.Skip Robinson > Southern California Edison Company > Electric Dragon Team Paddler > SHARE MVS Program Co-Manager > 626-302-7535 Office > 323-715-0595 Mobile > jo.skip.robin...@sce.com > > > > From: Ed VanBebber <edmond.vanbeb...@state.ca.gov> > To: IBM-MAIN@LISTSERV.UA.EDU, > Date: 06/06/2013 11:34 AM > Subject: XRC Volume Resync on a Return Home > Sent by: IBM Mainframe Discussion List <IBM-MAIN@LISTSERV.UA.EDU> > > > > After running production in a recovery site for some time, if you want to > return operations back to the original application region, does XRC do a > full volume resync or an incremental resync? > > I've read that XRC can do an incremental resync when returning home if you > are configured with region switch and running GDPS, which we are not. Does > anyone know if this is a proprietary thing? -- Mike A Schwab, Springfield IL USA Where do Forest Rangers go to get away from it all? ---------------------------------------------------------------------- For IBM-MAIN subscribe / signoff / archive access instructions, send email to lists...@listserv.ua.edu with the message: INFO IBM-MAIN
