HP StorageWorks XP Remote Web Console Software - Manual (Page 21)

metadata area usable, you need to split (suspend) all the data volume pairs in the journal
group and then restore (resynchronize) the pairs.
Adding journal volumes during a remote copy operation will not decrease the metadata usage
rate if the metadata usage rate is high.
Adding journal volumes during a remote copy operation may not change the journal data
usage rate until the journal volumes are used. To check the journal data usage rate, use the
Usage Monitor window (see
“Usage Monitor Window” (page 122) ).
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Deleting journal volumes.
You can delete journal volumes under any of the following conditions:
◦ When the journal group does not contain data volumes (that is, before you create a data
volume pair for the first time in the journal group or after all data volume pairs are
released)
◦ When all data volume pairs in the journal group are suspended.
You can use Remote Web Console computers to delete journal volumes.
CAUTION: If you delete a mainframe journal volume from a journal group where a data
volume pair has ever been registered, the deleted volume (LDEV) will be blocked. To reuse
the volume as a data volume, you must format the volume by using Virtual LVI/LUN (VLL).
Unless you format the volume, data in the volume will not be guaranteed.
For instructions on formatting volumes, see the HP XP24000/XP20000 Virtual LVI/LUN (VLL)
and Volume Shredder User's Guide. Note that you do not need to format the volume if you
want 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
“Metadata Information” (page 30) . The journal data that the metadata
manages is stored in the journal data area.
If the journal data cannot be stored for the length of time specified by the timeout period (data
overflow watch) because the journal data area is full, the journal group is suspended with an error.
The Remote Web Console computer can be used to specify the timeout period as a journal group
option. The timeout period must be between 0 and 600 seconds. For details on journal group
options, see
“Changing Options for a Journal Group” (page 167) .
If the meta data area becomes full before the timeout period expires, the journal group is suspended
with an error.
Journal Group
A 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 Universal
Replicator for Mainframe 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
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