HP XP P9000 Continuous Access Synchronous for Mainframe Systems User Guide

Figure 2 Extender Connection
• Set port topology to the following:
NL/FL port: Fab on, FC-AL◦
◦ F port: Fab on, Point-to-Point
• Best practice is to create at least two independent data paths (one per cluster) between the
main and remote system for hardware redundancy for this critical element.
• When 4,000 pairs or more are used, we recommend that you restrict the number of pairs
when creating pairs, so that 4,000 pairs or less use one physical path, to distribute load on
the physical path.
Ports
Data is transferred along the data path from the initiator to the RCU target ports on the main and
remote system. The amount of data each of these ports can transmit is limited.
Therefore, you must know the amount of data that will be transferred (write-workload) during peak
periods. You can then ensure not only that bandwidth meets data transfer requirements, but that
a sufficient number of each system’s ports are specified as initiator and RCU target ports to handle
all workload levels.
Port attributes and requirements
Plan and define the following Fibre Channel port attributes for Cnt Ac-S Z:
• Initiator ports, which send data. One initiator port can be connected to a maximum of 64
RCU target ports. Configure initiator ports on both main and remote system for Cnt Ac-S Z
disaster recovery operations.
XP P9500 automatically configures a Fibre Channel port as an initiator or RCU target in
response to the TSO CESTPATH and CDELPATH commands. See system option mode 114 in
“S-VOL Read and other system options” (page 29).
NOTE: Do not use the CESTPATH and CDELPATH commands to configure a Fibre Channel
port at the same time that the SCSI path definition function for LUN Manager is in use.
• RCU target ports, which receive data. Configure RCU target ports on both main and remote
system for Cnt Ac-S Z disaster recovery operations.
One remote system port can be connected to a maximum of 16 ports on a main system. The
number of logical paths that can be specified does not depend on the number of ports
configured for Cnt Ac-S Z.
• Target port: Connects the storage system and a host. When the host issues a write request,
the request is sent to a volume on the XP P9500 system through a target port on the storage
system. Target ports must be configured on the main system for Cnt Ac-S Z operations.
• External port: Required for External Storage copy operations. This port is not used for Cnt
Ac-S Z copy operations. This port can be changed to a target, initiator, or RCU target port.
Data path requirements and configurations 49