Journal groups, Data volume pairs, Journal volumes – HP StorageWorks XP Remote Web Console Software User Manual
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Continuous Access XP Journal
disk array issues the read journal command to the primary disk array and copies journals. For
Command View XP, the secondary management station should be connected to the secondary disk
arrays at the secondary site on a separate LAN. The secondary disk arrays should also be attached to
a host system to report sense information if a problem with a secondary data volume or secondary disk
array occurs and provide disaster recovery capabilities.
The XP10000/XP12000 can function simultaneously as a primary disk array for one or more primary
data volumes and as an secondary disk array for one or more secondary data volumes if the remote copy
connections and fibre-channel interface ports are properly configured. You can use Continuous Access XP
Journal to specify the secondary disk array from the connected primary disk array. Continuous Access XP
Journal operations can be performed on all LDEVS except for Command View XP or XP Remote Web
Console command devices. For more information, see the HP StorageWorks LUN Configuration and
Security Manager XP User Guide for the XP10000/XP12000.
NOTE:
When you configure a Continuous Access XP Journal journal group pair, you must specify the
serial numbers of the primary and secondary disk arrays. You must specify different serial numbers for the
primary disk array and secondary disk array for the same Continuous Access XP Journal journal group
pair. If you must specify the same serial number, contact your HP account support representative.
Journal groups
A journal group consists of two or more data volumes and journal volumes. You can use a journal group to
tailor Continuous Access XP Journal for your unique business content. The journal volume in the primary
disk array is referred to as the master journal volume. The journal volume in the secondary disk array is
referred to as the restore journal volume. The data volume in the master journal group is also called the
primary data volume. The journal volume in the master journal group is called the master journal volume.
The data volume in the restore journal group is similarly called the secondary data volume. The journal
volume in the restore journal group is called the restore journal volume.
The data update sequence from the host is managed based on 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 based on 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.
Data volume pairs
Continuous Access XP Journal performs remote copy operations for data volume pairs that you create.
Each Continuous Access XP Journal pair consists of one primary data volume and one secondary data
volume, which can be located in different disk arrays. Continuous Access XP Journal primary data volumes
are the primary volumes (LUs) containing the original data. Continuous Access XP Journal secondary
volumes are the secondary volumes (LUs) containing the backup or duplicate data. During normal
Continuous Access XP Journal operations, the primary data volume remains available to all hosts at all
times for read and write I/O operations. During normal Continuous Access XP Journal operations, the
secondary disk array 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
Continuous Access XP Journal also supports custom volume and HP Cache LUN XP, which allows
Continuous Access XP Journal to meet a variety of user needs and allows data copying and data
migration. This ensures that all user data can be backed up or duplicated. See ”
page 36 for more information about LU requirements and support.
Journal volumes
When you use Continuous Access XP Journal, updates to primary data volumes can be stored in other
volumes, which are called journal volumes. 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