HP StorageWorks XP Remote Web Console Software - Manual (Page 19)

Any Fibre Channel interface port on the XP storage system 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 a 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 Universal Replicator for Mainframe 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 “Configuring Port Attributes” (page 139) for information on configuring the host interface port.
Data Volume Pair
Universal Replicator for Mainframe performs remote copy operations for data volume pairs created
by the user. Each Universal Replicator for Mainframe pair consists of one primary data volume
and one secondary data volume, which can be located in different storage systems. The Universal
Replicator for Mainframe primary data volumes are the primary volumes (LDEVs) which contain
the original data, and the Universal Replicator for Mainframe secondary data volumes are the
secondary volumes (LDEVs) which contain the backup or duplicate data. During normal Universal
Replicator for Mainframe operations, the primary data volume remains available to all hosts at all
times for read and write I/O operations. During normal Universal Replicator for Mainframe
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
“Secondary Data Volume Write Option” (page 29) ).
Universal Replicator for Mainframe also supports the Virtual LVI/LUN (VLL) and Cache Residency
Manager features, so that Universal Replicator for Mainframe 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
“Duplicate VOLSER ” (page 51) for further information on LU requirements and
support.
IMPORTANT: If you connect the IBM OS installed host and the Fujitsu OS installed host to a same
storage system, call HP technical support when creating a Universal Replicator for Mainframe pair
by using volumes that are connected by IBM OS installed host.
Journal Volume
When Universal Replicator for Mainframe is used, updates to primary data volumes can be stored
in other volumes, which are called journal volumes. The updates (which are sometimes referred to
as update data) that will be stored in journal volumes are called journal data.
Because journal data will be stored in journal volumes, you can perform and manage highly
reliable remote copy operations without suspension of remote copy operations. For example, even
if a communication path between the primary storage system and the secondary storage system
fails temporarily, remote copy operations can continue after the communication path is recovered.
If data transfer from hosts to the primary storage system is temporarily faster than data transfer
between the primary storage system and the secondary storage system, remote copy operations
between the primary storage system and the secondary storage system can continue. Because
journal volumes can contain a lot more update data than the cache memory can contain, remote
copy operations can continue if data transfer from hosts to the primary storage system is faster for
a relatively long period of time than data transfer between the primary storage system and the
secondary storage system.
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