HP StorageWorks XP Remote Web Console Software - Manual (Page 63)

Table 18 Journal Group Specifications
Item Support specifications
Number of journal groups Up to 256 journal groups (No. 0 - 255) per one storage subsystem
NOTE:
The recommended number of journal groups is up to 16
Number of data volumes in a journal
group
Up to 4,096
Number of journal volumes in a journal
group
Up to 64
Number of Mirror IDs Up to 4 (ID No.: 0 to 3)
NOTE:
If TCz Sync. uses No. 0, No. 1 to 3 are available for URz.
The same number of journal volumes is not required in the master journal group and the restore journal
group that are paired.
Mirror ID is required for the configuration that will be supported in the future within the 3-data center
(3DC), including the expected future enhancement to enable the user to pair one master journal group with
two or more restore journal groups. Each pair relationship in a journal group is called "Mirror." Mirror ID
identifies two or more mirrors that one journal group has. The same Mirror ID of the journal group is
applied to the data volume pair. See“ TCz Synchronous (3DC Cascading Configuration) ” on page 89.
• Table 19 on page 63 shows the specifications of relationship between the data volumes, between
the journal volumes, and between the data volumes and journal volumes in a journal group.
Table 19 Journal Group Volume Specifications
Item Support specifications
Emulation
type
Same emulation type.
Volume
capacity
Does not matter whether the capacity is the same or different.
CLPR Journal volumes and data volumes in the same journal group can belong to different
CLPRs. Journal volumes must belong to the same CLPR. Data volumes must also belong
to the same CLPR.
A primary journal group and the corresponding restore journal group need not belong
to the same CLPR.
NOTE:
When URz and UR coexist in the same storage system, each journal group must contain either URz pairs
or UR pairs (not both).
Accessing URz Primary Data Volume and Secondary Data Volume
To ensure maximum data integrity during normal URz operations, the secondary storage system rejects
all the read/write operations issued by a host to a URz secondary data volume. If you need write
operation to a URz secondary data volume, you must set the secondary data volume write option (see
“ Secondary Data Volume Write Option ” on page 36). When you resume (Resume Pair) the split pair,
the secondary storage system will send the secondary data volume track bitmap to the primary storage
system to ensure proper resynchronization of the pair.
Hitachi Universal Replicator for z/OS user guide for XP12000/XP10000 Disk Arrays and SVS 200 63