Planning Ports For Data Transfer; Determining Required Number Of Ports - HP StorageWorks P9000 User Manual

Planning ports for data transfer

Updated data is transferred along the data path from the initiator and RCU target ports on the
primary and secondary systems.
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 during peak periods. Then your need
to insure that a sufficient number of your systems' ports are specified as initiator and RCU target
ports to handle the potential amount of data.
The Fibre Channel ports on P9500 systems can have the following attributes:
Target port: Connects the storage system and an open systems host. When the host issues a
write request, the request is sent to a volume on the P9500 system via a target port on the
storage system. Target ports must be configured on primary storage systems for Continuous
Access Journal operations.
Initiator port: Sends Continuous Access Journal commands to the paired storage system.
initiator ports must be configured on both primary and remote storage systems for Continuous
Access Journal operations.
RCU Target port: Receives Continuous Access Journal commands and data. RCU target ports
must be configured on both primary and remote storage systems for Continuous Access Journal
operations.
External port: Required for External Storage copy operations. This port is not used for
Continuous Access Journal copy operations. This port can be changed to a target, initiator,
or RCU target port.
NOTE: Two or more initiator ports must be configured before you can add the secondary storage
systems and create the Continuous Access Journal volume pairs.

Determining required number of ports

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.
Adding more ports increases the amount of data that can be transferred between systems.
To determine the required number of initiator and RCU target ports
P9500 ports are designated as target ports by default. When you determine the number of initiator
ports and RCU target ports your Continuous Access Journal system requires, you change port
attributes from target to initiator and RCU target.
1. Maximum IOPS threshold is set by the factory for the Fibre Channel ports and their
microprocessors. One microprocessor manages the data traffic for two Fibre Channel ports.
Contact your factory representative to find out the IOPS threshold of your port microprocessors.
2. Measure IOPS for your production system. IOPS is provided when write-workload is measured.
(See "Measuring write-workload" (page 21).)
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