HP Mainframe Connectivity Design Guide

GDPS configurations
There are three GDPS configurations, determined by the distance between sites, the disk replication
method, and whether the Sysplex Timers and/or coupling links connect the mainframes.
• GDPS/PPRC—Uses synchronous PPRC and/or a coupling facility to connect the mainframes.
This is limited to a WDM or dark fiber circuit and has a maximum circuit distance of
approximately 100 km. IP gateways are not certified for GDPS/PPRC. You can use HP FICON
directors and P9500 and XP storage systems in a GDPS/PPRC configuration.
• GDPS/Global Mirror—Uses asynchronous PPRC and/or a coupling facility to connect the
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mainframes. This is limited to a WDM or dark fiber circuit and has a maximum circuit distance
of approximately 100 km. IP gateways are not certified for GDPS/Global Mirror. You can
use HP FICON directors in a GDPS/Global Mirror configuration.
NOTE: Neither P9500 nor XP arrays are supported in a GDPS/Global Mirror environment.
• GDPS/XRC—Uses XRC to replicate data between data centers. This solution supports an
unlimited distance; the mainframes in different data centers are not connected using Sysplex
Timers or coupling facilities. You can use HP FICON directors and P9500 or XP storage
systems in a GDPS/XRC configuration. Some IP gateway products are certified for GDPS/XRC;
the supported distance varies depending on the IP gateway product. For more information,
see “Mainframe-controlled replication”.
Direct access storage device
Mainframe DASD extension is used primarily for replication methods rather than direct
CHPID-to-DASD extension because of performance limitations.
This section describes the two mainframe DASD replication methods.
Controller-to-controller replication
HP P9000/XP Continuous Access software offers controller-to-controller replication using the Fibre
Channel protocol and Fibre Channel ports (not FICON ports) on the storage system to replicate
data from the source to the target.
The HP P9000 Continuous Access software family of products includes HP P9000 Continuous
Access Synchronous software and HP P9000 Continuous Access Journal software.
The HP XP Continuous Access software family of products includes HP XP Continuous Access
Synchronous software and HP XP Continuous Access Journal software.
If the distance between the source and the target is short, synchronous remote replication is typically
used. However, as the distance increases between the source and the target, network delays make
asynchronous remote replication a better choice. For longer distances, HP recommends that you
use HP P9000 Continuous Access Journal or HP XP Continuous Access Journal. For more information
about HP P9000/XP Continuous Access software, see HP SAN Design Reference Guide.
P9500 and XP storage systems support PPRC commands.
Mainframe-controlled replication
Mainframe-controlled replication uses an SDM application running on at least one LPAR. This is
commonly referred to as XRC, also known as IBM TotalStorage z/OS Global Mirror.
P9500 and XP storage systems support XRC. This section provides an overview of XRC; it is not
intended to be a product specification.
Sample XRC configuration
The following process occurs in the sample XRC configuration shown in Figure 16 (page 125):
124 FICON and FICON SAN extension