HP StorageWorks XP Remote Web Console Software - Manual (Page 27)

Journal volumes in the same journal group can be of different capacity. A master journal volume and
the corresponding restore journal volume can be of different capacity.
A journal volume consists of two areas: one area is used for storing journal data, and the other area
is used for storing metadata for remote copy.
• RAID configuration:
Journal volumes support all RAID configurations that are supported by XP. Journal volumes also
support all physical volumes that are supported by XP disk array.
• Support for program products:
The volumes on which Cache Residency Manager settings are made can be used for journal volumes.
Caution: Volumes containing a VMA (volume management area) cannot be used as journal volumes. For
detailed information about a VMA, please refer to the Data Retention Utility User’s Guide.
Restrictions on Journal Volumes
• Registering journal volumes:
Caution: 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 (i.e., 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
If a path is defined from a host to a volume, you cannot register the volume as a journal volume.
You can use XP Remote Web Console computers to register journal volumes.
If you add a journal volume when a remote copy operation is in progress (i.e., 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 ” on page 171.
• Deleting journal volumes:
You can delete journal volumes under any of the following conditions:
• When the journal group does not contain data volumes (i.e., 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 XP 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. If you want 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.
Hitachi Universal Replicator for z/OS user guide for XP12000/XP10000 Disk Arrays and SVS 200 27