HP StorageWorks XP Remote Web Console Software - Manual (Page 32)

2-10 Chapter 3 Preparing for Universal Replicator z/OS Operations
Hitachi Universal Replicator for IBM /OS User’s Guide
Initiator Ports and RCU Target Ports
The initiator port and the RCU target port are required at both the primary
storage system and secondary storage system. The initiator port at the
primary storage system is connected to the RCU target port at the secondary
storage system via the fibre channel interface. The initiator port at the
secondary storage system is connected to the RCU target port at the primary
storage system. The initiator port at the secondary storage system issues a
"read journal" command to the primary storage system, and then the RCU
target port at the primary storage system sends journal data to the secondary
storage system in response to the "read journal" command.
Any fibre-channel interface port of the USP V can be configured as an initiator
port. The initiator ports cannot communicate with the host processor channels.
The host channel paths must be connected to the fibre-channel interface port
other than the initiator port.
Note: Two or more initiator ports must be configured before you can add the
secondary storage systems and create the URz volume pairs.
The fibre-channel interface ports that are assigned for the RCU target ports
can be connected to the host channel paths via the fibre-channel switch.
See section Configuring Port Attributes for the information on configuring host
interface port.
Data Volume Pair
URz performs remote copy operations for data volume pairs created by the
user. Each URz pair consists of one primary data volume and one secondary
data volume which can be located in different storage systems. The URz
primary data volumes are the primary volumes (LDEVs) which contain the
original data, and the URz secondary data volumes are the secondary volumes
(LDEVs) which contain the backup or duplicate data. During normal URz
operations, the primary data volume remains available to all hosts at all times
for read and write I/O operations. During normal URz operations, the
secondary storage system rejects all host-requested write I/Os for the
secondary data volume. The secondary data volume write enable option allows
write access to a secondary data volume while the pair is split and uses the
secondary data volume and primary data volume track maps to resynchronize
the pair (see section Secondary Data Volume Write Option).
URz also supports the Virtual LVI/LUN (VLL) and Cache Residency Manager
features, so that URz meets a variety of user needs and facilitates data
copying and data migration. This ensures that all user data can be backed up
or duplicated. See section Duplicate VOLSER (Volume Serial Number) for
further information on LU requirements and support.