HP XP7 Storage - Manual (Page 46)

The secondary system initiator port sends journal query commands to the primary RCU target port.
The data is then sent through these ports — that is, from primary side RCU target ports to secondary
system initiator ports.
Note the following:
•
An initiator port on one side must have an RCU target port on the other side.
•
Two or more initiator ports must be configured before you can create the Cnt Ac-J Z relationship
with the secondary system and create pairs.
•
The amount of data each of port can transmit is limited. Therefore, it is critical to know the
amount of data that will be transferred during peak periods. This knowledge will ensure that
you can set up a sufficient number of ports as initiator and RCU target ports in order to handle
all workloads.
•
If your Cnt Ac-J Z system supports a disaster recovery failover/failback environment, initiator
and RCU target ports should be sized equivalently on primary and secondary systems.
•
Up to eight paths can be established in both directions. It is recommended that you establish
at least two independent data paths to provide hardware redundancy.
•
Host paths cannot be connected to an initiator port. However, they can be attached to RCU
target ports.
Example configuration
•
Two initiator ports on the local side, with two matching RCU target ports on the remote side
•
Four initiator ports on the remote side, with four matching RCU target ports on the local side.
Port types
The primary and secondary systems require both initiator and RCU target ports. Both systems send
and receive traffic during active replication.
•
The initiator port on the primary side is connected to the RCU target port on the secondary
side.
•
The initiator port on the secondary side is connected to the RCU target port on the primary
side.
XP7 ports are designated as target ports by default. When you determine the number of initiator
ports and RCU target ports your Cnt Ac-J Z system requires, you change port attributes from target
to initiator and RCU target.
The fibre-channel ports on XP7 systems can have the following attributes:
•
Initiator port: Sends Cnt Ac-J Z commands to the paired system. Initiator ports must be
configured on both primary and secondary systems for pair operations.
Two or more initiator ports must be configured before you can add the secondary systems
and create pairs.
•
RCU Target port: Receives Cnt Ac-J Z commands and data. RCU target ports must be configured
on both primary and secondary storage systems for pair operations.
•
Target port: Connects the system and an open systems host. When the host issues a write
request, the request is sent via a target port to a volume on the XP7 system. Target ports are
not used with mainframe volumes or Cnt Ac-J Z operations. This port can be changed to an
initiator, or RCU target port.
•
External port: Required for External Storage copy operations. This port is not used for Cnt Ac-J
Z copy operations. This port can be changed to a target, initiator, or RCU target port.
46 Planning the data path