Data consistency was one of two reasons we chose circa 2000 to use XRC rather than PPRC. I know the technology has changed, and I've been *told* that PPRC is now capable of maintaining consistency, but I have not seen it in action. The other reason for XRC BTW was the synchronizing problem: we could not tolerate the I/O delay waiting for remote confirmation from 120 KM via ESCON. In 2000, everything was slower. Now we use DWDM via FICON.
. . 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 R.S. Sent: Thursday, June 07, 2018 4:10 AM To: [email protected] Subject: (External):Re: PPRC-XD vs Async PPRC W dniu 2018-06-06 o 18:18, Sankaranarayanan, Vignesh pisze: > Hello All, > > Please could you point me to any doc explaining the differences between the 2. > Any important, obscure, techdocs or KB page or some such as well.. ? Fundamental difference is data consistency. PPRC-XD is *inconsistent* copy during most of the time. Inconsistent is unusable. You have to quiesce the production and wait a little until the delta become zero (the copy become consistent). Asynchronous copy like XRC, SRDF/A, HARC is different. It is *consistent* copy - data on secondary site is usable, but is not current. Of course the time delta is small, but the most important is you don't have later data while earlier data is missing. -- Radoslaw Skorupka Lodz, Poland ---------------------------------------------------------------------- For IBM-MAIN subscribe / signoff / archive access instructions, send email to [email protected] with the message: INFO IBM-MAIN
