Pair status – HP StorageWorks XP Remote Web Console Software User Manual
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The status of the Universal Replicator for Mainframe pair will change to Duplex, not Pending Duplex.
This is because delta resync operation uses journal copy to copy only the necessary data. Because
of this efficiency, compared to the usual way that copies all the data in the primary data volume,
the delta resync operation takes less time to recover a Universal Replicator for Mainframe pair
after a failure occurs.
NOTE:
When the total capacity of stored journal data exceeds 80% of the journal volume of the
TrueCopy for Mainframe Synchronous secondary site, old journal data is automatically deleted.
Therefore, if the total capacity of the journal data (which is not restored to the Universal Replicator
for Mainframe secondary data volume) exceeds 80% of the journal volume, the secondary data
volume will not be completely restored by copying the journal data to the restore journal volume
in the Universal Replicator for Mainframe secondary site. In that case, according to the setting of
the journal group option, the entire data in the primary data volume is copied to the secondary
data volume, or the delta resync operation finishes without any processing.
Usually, if the TrueCopy for Mainframe Synchronous primary site and secondary site pair is
synchronized periodically, the total capacity of the journal data that is not restored to the Universal
Replicator for Mainframe secondary site does not exceed 80% of the journal volume. However, if
the Universal Replicator for Mainframe pair is suspended (and the pair has not been resynchronized
for a long time), stored journal data could exceed 80% of the journal volume capacity before they
are restored to Universal Replicator for Mainframe secondary data volume. In that case, note that
you may not perform the delta resync operation properly.
CAUTION:
Even if the capacity of the journal data does not exceed 80% of the journal volume,
note that journal data may be destroyed in the following cases:
•
When you restore the TrueCopy for Mainframe Synchronous pair, and then update the M-VOL.
•
When you restore the Universal Replicator for Mainframe pair between the primary site and
the Universal Replicator for Mainframe secondary site, and then update the M-VOL.
•
When the retry processing occurs because of a delay of the M-VOL update.
•
When the update of the TrueCopy for Mainframe Synchronous R-VOL is delayed.
CAUTION:
To use the Universal Replicator for Mainframe pair for delta resync operation as the
master journal group, after a power supply failure occurs at the primary site, you must resynchronize
the pair and then execute the I/O operation from the host.
As shown in
, after the delta resync operation is performed properly and the
primary site A is recovered from the failure, the Universal Replicator for Mainframe pair (between
the primary site A and the Universal Replicator for Mainframe secondary site) becomes the pair
for the delta resync operation and is thus prepared for the failure in the primary site B. For
information about the requirements to perform the delta resync operation properly, see
for Performing a Delta Resync Operation” (page 87)
Pair Status
Universal Replicator for Mainframe displays the pair status for each data volume of a specified
CUI in the connected storage system.
lists and describes the Universal Replicator
for Mainframe data volume pair status descriptions. The primary storage system maintains the
status of the primary data volume and can change the pair status of the primary data volume and
secondary data volume. The secondary storage system maintains the status of the secondary data
volume and can change the pair status of the secondary data volume but not the primary data
volume. The primary storage system will detect when the secondary storage system changes the
secondary data volume status (if the path status is normal) and will change the primary data volume
status accordingly. You can display the detailed pair status information on the Remote Web Console
remote console computer (Universal Replicator for Mainframe Pairdisplay window) or on the host
processor (Business Continuity Manager Pairdisplay command).
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About Universal Replicator for Mainframe Operations