HP StorageWorks XP Remote Web Console Software - Manual (Page 28)

For instructions on formatting volumes, please refer to the Virtual LVI/LUN and Volume Shredder
User’s Guide. The volume does not need to be formatted in order to register the deleted volume
as a journal volume again.
• Access from hosts to journal volumes:
If a path is defined from a host to a volume, you cannot register the volume as a journal volume.
You cannot define paths from hosts to journal volumes. This means that hosts cannot read from
and write to journal volumes.
Journal Volume Areas
The journal volume consists of the metadata area and the journal data area. The ratio of metadata area
to journal data area is common in the journal volumes within the journal group.
In the metadata area, the metadata that manages the journal data is stored. For further information on
the metadata area, see Table 3 on page 37. The journal data that the metadata manages is stored in
the journal data area.
If the metadata or the journal data cannot be stored for a given length of time because the metadata
or journal data areas have become full with the metadata or the journal data that had not been
discarded, the pair is suspended according to a failure. Users can use an XP Remote Web Console
computer to specify this timeout period (Data overflow watch) as a journal group option. This timeout
period must be within the range of 0 to 600 seconds. For details on journal group options, see
“ Changing Options for a Journal Group ” on page 138.
Remote Copy Connections
The remote copy connections are the physical paths used by the primary storage systems to communicate
with the secondary storage systems. Remote copy connections enable communication between the
primary and secondary storage systems. The primary storage systems and secondary storage systems
are connected via fibre-channel interface cables. You must establish paths from the primary to the
secondary storage system, and also from the secondary to the primary storage system. Up to eight paths
can be established in both of these directions.
When fibre-channel interface (optical multimode shortwave) connections are used, two switches are
required for distances greater than 0.5 km (1,640 feet), and distances up to 1.5 km (4,920 feet, 0.93
miles) are supported. If the distance between the primary and secondary sites is greater than 1.5 km,
the optical single mode long wave interface connections are required. When fibre-channel interface
(single-mode long wave) connections are used, two switches are required for distances greater than 10
km (6.2 miles), and distances up to 30 km (18.6 miles) are supported.
See “
Setting up Remote Copy Connections ” on page 65 for further information on installing and
configuring the FC remote copy connections.
The URz remote copy configuration between primary storage system and secondary storage system has
the following requirements:
URz supports 1-to-1 remote copy connection in one journal group pair. In one journal group pair, one
primary storage system can be connected to only one secondary storage system. This configuration
ensures the backup data consistency of two or more volumes (e.g., large databases) within the same
storage system.
HP strongly recommends that you establish at least two independent remote copy connections from the
primary storage system to the secondary storage system and vice versa to provide hardware redundancy
for this critical communications path.
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
28 Overview of Universal Replicator Operations