HP StorageWorks XP Remote Web Console Software - Manual (Page 13)

Main and Remote Control Units
The main control unit (primary storage system) and remote control unit (secondary storage system)
control URz operations:
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The primary storage system is the control unit in the primary storage system which controls
the primary data volume of the URz pairs and master journal volume. The XP Remote Web
Console remote console PC must be LAN-attached to the primary storage system. The primary
storage system communicates with the secondary storage system via the dedicated remote
copy connections. The primary storage system controls the host I/O operations to the URz
primary data volume and the journal obtain operation of the master journal volume as well
as the URz initial copy and update copy operations between the primary data volumes and
the secondary data volumes.
•
The secondary storage system is the control unit in the secondary storage system which controls
the secondary data volume of the URz pairs and restore journal volume. The secondary storage
system controls copying of journals and restoring of journals to secondary data volumes. The
secondary storage system assists in managing the URz pair status and configuration (for
example, rejects write I/Os to the URz secondary data volumes). The secondary storage system
issues the read journal command to the primary storage system and executes copying of
journals. The secondary XP Remote Web Console PC should be connected to the secondary
storage systems at the secondary site on a separate LAN. The secondary storage systems
should also be attached to a host system to allow sense information to be reported in case of
a problem with a secondary data volume or secondary storage system and to provide disaster
recovery capabilities.
The XP disk array can function simultaneously as a primary storage system for one or more primary
data volumes and as a secondary storage system for one or more secondary data volumes, provided
the remote copy connections and Fibre Channel interface ports are properly configured. The URz
software allows you to specify the secondary storage system from the connected primary storage
system. URz operations can be performed on all LDEVs except for the XP disk array command
device. For further information on the XP disk array command device, see the HP StorageWorks
XP RAID Manager user guide.
When you configure a URz journal group pair, you have to specify the serial numbers of primary
storage systems and secondary storage systems. You have to specify the different serial numbers
of primary storage system and secondary storage system for the same URz journal group pair. If
you have to specify the same serial number, contact your HP account team.
Journal Group
Journal group consists of two or more data volumes and journal volumes. It is a feature that allows
you to sort multiple data volumes and journal volumes into collective units to tailor URz to meet
your unique business needs. The journal group in the primary storage system is referred to as the
master journal group. The journal group in the secondary storage system is referred to as the restore
journal group. The data volumes in the master journal group are also called the primary data
volumes. The journal volumes in the master journal group are called the master journal volumes.
The data volumes in the restore journal group are similarly called the secondary data volumes.
The journal volumes in the restore journal group are called the restore journal volumes.
The data update sequence from the host is managed per the journal group. The data update
sequence consistency between the master and restore journal groups to be paired is maintained
and ensured. The master and restore journal groups are managed according to the journal group
number. The journal numbers of master and restore journal groups that are paired can be different.
One data volume and one journal volume can belong to only one journal group.
URz Components 13