Software Manual

CAUTION:
You must register journal volumes in a journal group before creating a data volume pair in the
journal group for the first time.
You can add journal volumes under any of the following conditions:
• The journal group does not contain data volumes (that is, before creating a data volume pair
in the journal group for the first time, or after deleting all data volume pairs)
• All data volume pairs in the journal group are suspended
• Processing for changing a data volume pair's status (for example, deleting or suspending a
data volume pair) is not in progress
NOTE:
Ifapathfromahosttoavolumeisdefined, you cannot register the volume as a journal volume.
You can use Command View XP management stations or XP Remote Web Console to register
journal volumes.
Ifyouaddajo
urnalvolumewhenaremotecopyoperationisinprogress(thatis,whenatleastone
data volume p
air exists for data copying), the journal volume's metadata area (see Journal volume
areas) is unused, and only the journal data area is used. To make the metadata area usable, split
(suspend) all data volume pairs in the journal group, and restore (resynchronize) the pairs.
Adding jour
nal volumes during a remote copy operation does not decrease the metadata usage rate
if the metad
ata usage rate is high.
Adding journal volumes during a remote copy operation might not change the journal data usage
rate until the journal volumes are used. To check the journal data usage rate, use the Usage Monitor
pane (see Mo
nitoring remote copy operations).
• Deleting journal volumes
You can delete journal volumes under any of the following conditions:
• The journal group does not contain data volumes (that is, before creating a data volume pair
in the journal group for the first time, or after deleting all data volume pairs)
• All data v
olume pairs in the journal group are suspended
You can use Command View XP management stations or XP Remote Web Console to delete journal
volumes.
• Access fr
om hosts to journal volumes
Ifapathfromahosttoavolumeisdefined, 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
A journal volume consists of a metadata area and a journal data area. The ratio of the metadata area to
the journal data area is the same on all journal volumes within the journal group.
Metadata that manages the journal data is stored in the metadata area. For more information about the
metadata area, see Table 3. Journal data that the metadata manages is stored in the journal data area.
Continuous Access XP Journal user guide
25