Cache and nonvolatile storage, Duplicate volumes – HP StorageWorks XP Remote Web Console Software User Manual
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of the journal group is applied to the data volume pair. For 3DC configurations, see
for Mainframe Synchronous (3DC Cascading Configuration)” (page 79)
•
shows the specifications of the relationship between the data volumes,
between the journal volumes, and between the data volumes and journal volumes in a journal
group.
Table 20 Journal Group Volume Specifications
Support specifications
Item
Same emulation type.
Emulation type
Does not matter whether the capacity is the same or different.
Volume capacity
Journal volumes and data volumes in the same journal group can belong
to different CLPRs. Journal volumes must belong to the same CLPR.
NOTE:
A primary journal group and the corresponding restore journal
group need not belong to the same CLPR.
CLPR
NOTE:
When Universal Replicator for Mainframe and XP Continuous Access coexist in the same
storage system, each journal group must contain either Universal Replicator for Mainframe pairs
or XP Continuous Access pairs (not both).
Accessing Universal Replicator for Mainframe Primary Data Volume and Secondary
Data Volume
To ensure maximum data integrity during normal Universal Replicator for Mainframe operations,
the secondary storage system rejects all the read/write operations issued by a host to a Universal
Replicator for Mainframe secondary data volume. If you need the write operation to a Universal
Replicator for Mainframe secondary data volume, you must set the secondary data volume write
option (see
“Secondary Data Volume Write Option” (page 29)
). 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.
Cache and Nonvolatile Storage
Cache and NVS must be operable for both the primary storage system and secondary storage
system of a Universal Replicator for Mainframe data volume pair. If not, the Universal Replicator
for Mainframe add pair operation will fail. The remote storage system cache should be configured
to adequately support not only the local workloads but also the Universal Replicator for Mainframe
remote copy workloads.
When the pair status is Pending, neither cache nor shared memory can be added to or removed
from the storage system. When either of these tasks is to be performed, first split all pairs in Pending
status, then resynchronize when the cache or shared memory operation is complete.
Duplicate Volumes
Since the contents of the primary data volume and secondary data volume of a Universal Replicator
for Mainframe pair are identical, the secondary data volume can be considered a duplicate of
the primary data volume. Since the host operating system does not allow duplicate volumes, the
host system administrator must take precautions to prevent system problems related to duplicate
volumes. You must define Universal Replicator for Mainframe secondary data volumes so they do
not auto-mount or come online to the same host at the same time as the primary data volume (see
the CAUTION below).
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Preparing for Universal Replicator for Mainframe Operations