On Tue, 14 Jul 2020 12:16:37 +0200, R.S. <[email protected]> wrote:
>I hate new names of PPRC and XRC (and PPRC-XD), but... But one should >know there are new features. New features with new names, but no old >name exist for them. > >There are still PPRC, XRC, PPRC-XD, but there is also some kind of "XRC >without z/OS", performed by dasd arrays without host involvement. XRC = An architecture for time stamping I/Os across multiple Z systems. Any OS can do it. The time stamp is part of the I/O architecture. z/OS Global Mirror = An application that runs on a pair of z/OS systems. The local z/OS system gets copies of all write I/O to local copy of a mirrored volume. The local z/OS system sends the I/O to a remote z/OS system where the I/Os are placed in timestamp order and then written. It is an asynchronous tech driven by the host, it can be used with storage servers from different vendors. PPRC = Peer-to-Peer Remote Copy = I/O architecture that enables a pair of local storage controllers to maintain volume mirrors synchronously. RPO = 0 for the mirrors since I/O to the primary does not complete until I/O to the mirror is complete. Asynchronous PPRC = A slightly different version of PPRC for a pair of storage controllers that are too far away from each to be able to maintain I/O service times and the mirrors. RPO > 0 for the mirrors since I/O to the primary will complete before the I/O to the secondary is complete (or even started). NOTE: SRDF and PPRC are similar, but they are not compatible with each other.. Metro Mirror = Exploitation of PPRC to manage the local mirrors.. Global Mirror = Exploitation of aynch PPRC to manage remote mirrors. The names were changed to avoid dragging everyone down a rabbit hole as the tech changes underneath. HTH. Alan Altmark IBM ---------------------------------------------------------------------- For IBM-MAIN subscribe / signoff / archive access instructions, send email to [email protected] with the message: INFO IBM-MAIN
