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

Restrictions on Journal Volumes
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Registering journal volumes.
IMPORTANT: You must register journal volumes in a journal group before you create a data
volume pair for the first time in the journal group.
You can add 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.
◦ When processing for changing the status of a data volume pair (for example, release or
suspension of a data volume pair) is not in progress.
◦ When no Cache Residency Manager settings are set on the volumes.
NOTE: If a path is defined from a host to a volume, you cannot register the volume as a
journal volume.
You can use Remote Web Console computers to register journal volumes.
If you add a journal volume when a remote copy operation is in progress (that is, when at
least one data volume pair exists for data copying), the metadata area of the journal volume
(see the next section) will be unused and only the journal data area will be used. To make the
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 126) ).
•
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 StorageWorks 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.
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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.
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