HP XP P9500 Storage - Manual (Page 37)

Planning ports
Data is transferred along the data path from the initiator to RCU target ports on the main and
remote system.
•
Initiator ports send data.
•
RCU target ports receive data.
•
The amount of data each of these ports can transmit is limited.
You must know the amount of data that will be transferred (write-workload) during peak periods.
Then you can 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.
The Fibre Channel ports on P9500 systems can have the following attributes:
Target port: Connects the disk array and an open system host.
Initiator port: Sends Continuous Access Synchronous Z commands to the paired storage system.
Initiator ports must be configured on the main system for Continuous Access Synchronous Z
operations. When you want to copy data from the remote system to the main system, initiator ports
also must be configured on the remote system.
NOTE: P9500 automatically configures a Fibre Channel port as an initiator or RCU target, if
required, in response to the TSO CESTPATH and CDELPATH commands. See system option mode
114 in
Table 11 (page 26) .
For Fibre Channel interface, do not use the CESTPATH and CDELPATH commands at the same
time as the SCSI path definition function of LUN Manager
RCU Target port: Receives Continuous Access Synchronous Z commands and data. RCU target
ports must be configured on the remote system for Continuous Access Synchronous Z operations.
When you want to copy data from remote system to main system, RCU target ports also must be
configured on the main system.
External port: Required for External Storage copy operations. This port is not used for Continuous
Access Synchronous Z copy operations. This port can be changed to a target, initiator, or RCU
target port.
Initiator/external port: This setting shows the combination of ports that have an initiator port and
an external port attribute. Only a port that has an initiator port attribute within these ports can be
used for Continuous Access Synchronous Z. This attribute cannot be changed by the Continuous
Access Synchronous Z software. For details on the port to which an initiator/external mix mode
is set, see the HP P9000 External Storage for Open and Mainframe Systems User Guide.
Port requirements
Ports set up for Continuous Access Synchronous Z operations have the following max/min
requirements:
•
One initiator port can be connected to a maximum of 64 RCU target ports.
•
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 Continuous Access Synchronous Z.
Error reporting communications
Error reporting communications (ERC) transfers information between host processors at the main
and remote sites. It is a critical component of a disaster recovery effort.
Error reporting communications 37