HP XP Racks - Manual (Page 35)

Figure 1 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
primary and secondary 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.
•
The same write-workload would be used in the reverse direction in a disaster recovery scenario.
Therefore, when planning Continuous Access Synchronous for disaster recovery, the same
number of remote-to-local data paths should be set up as the local-to-remote copy paths for
normal operations. Reverse direction paths must be set up independently of the local-to-remote
paths.
•
When you set up remote-to-local data paths, specify the same combination of CUs or CU Free,
and the same path group ID, as specified for the local-to-remote paths.
Ports
Data is transferred along the data path from the initiator to the RCU target ports on the primary
and secondary 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 requirements
Note the following:
•
One secondary system port can be connected to a maximum of 16 ports on a primary system.
The number of remote paths that can be specified does not depend on the number of ports
configured for Continuous Access Synchronous. You can specify the number of remote paths
for each remote connection.
•
Make sure not to add or delete a remote connection, or add a remote path at the same time
that the SCSI path definition function for LUN Manager is in use.
Data path requirements and configurations 35