The storage administrator must identify application volumes to copy, and create peer-to-peer remote copy volume pairs. PPRC provides an image copy of a volume on a record-for-record basis. There is a one-to-one correspondence between the record on the primary volume track and the record on the secondary volume track. PPRC writes data on the same tracks on the secondary disk as it does on the primary disk. Therefore, the secondary disk must have the same track sizes and number of tracks per cylinder, and either the same or larger volume capacities, as the primary. If the disk does not meet these criteria, the CESTPAIR command will fail.
You should make secondary volumes part of a storage group that does not allow allocations, and dedicate these volumes to PPRC use only. PPRC secondary volumes are similar to 3390 dual copy secondary volumes. All host I/O operations directed to these offline secondary volumes are command rejected.
Remote copy supports volumes, not data sets. As a result, all data sets on the volumes that are copied are part of remote copy activity, and are therefore copied to the recovery system. This support is application (IBM® or non-IBM) independent, and supports all data set types.
Because applications deal with data sets and not volumes, multivolume data sets require special attention. Unless you copy all volumes of a multivolume data set, PPRC will only copy part of the data set. Other data sets on the copied volume may be usable, but the multivolume data sets will not be. If multivolume data sets are critical for recovery, you must also copy the other volumes on which these data sets reside.
Carefully choose the volumes to copy so as not to unnecessarily affect overall PPRC performance. Copying page data sets can affect performance.
It would be wasteful to have PPRC copy a volume that contains page or other data sets that are specific to the application host system.
For additional information about the CESTPAIR command, see CESTPAIR – establishing volume pairs.