Urz pair status – HP StorageWorks XP Remote Web Console Software User Manual
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In delta resync operation, the status of the URz pair will not change to Pending Duplex but Duplex. This is
because delta resync operation copies only the really necessary data by journal copying. Compared to
the usual way which copies the whole data in the primary data volume, delta resync operation requires
shorter time for the recovery of the URz pair after a failure occurs.
NOTE:
When the total capacity of stored journal data exceeds 80% of the journal volume of TCz Synchronous
secondary site, old journal data will be deleted automatically. Therefore, if the total capacity of the journal
data which is not restored to the URz secondary data volume exceeds 80% of the journal volume, the
secondary data volume will not be able to be restored completely by copying the journal data to the restore
journal volume in the URz secondary site. In that case, according to the setting of the journal group
option, whole data in the primary data volume will be copied to the secondary data volume, or delta
resync operation finishes without any processing.
Usually, if the pair between TCz Synchronous primary site and secondary site is synchronized periodically,
the total capacity of the journal data which is not restored to the URz secondary site will not exceed
80% of the journal volume. Though, for example if the URz pair is suspended and the pair has not been
resynchronized for a long time, journal data of more than 80% of the journal volume capacity may be
stored before they are restored to URz secondary data volume. In such case, you may not perform
delta resync operation properly.
WARNING!
Even if the capacity of the journal data does not exceed 80% of the journal volume, the journal data will or
may be destroyed in the following cases.
•
When you restore the TCz Synchronous pair, then updated the M-VOL
•
When you restore the URz pair between the primary site and the URz secondary site, then
updated the M-VOL
•
When the retry processing occurs because of a delay of the M-VOL update
•
When the update of the TCz Synchronous R-VOL is delayed
As shown in
on page 44, after delta resync operation is performed properly and the primary
site A is recovered from the failure, then the URz pair between the primary site A and the URz
secondary site will be the pair for delta resync operation and become prepared for the failure in the
primary site B. For information about the requirements to perform delta resync operation properly, see
Requirements for Performing Delta Resync Operation
URz Pair Status
URz displays the pair status for each data volume of specified CU Image (CUI) in the connected XP
storage system.
on page 47 lists and describes the URz 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 at the XP
Remote Web Console remote console PC (URz Pairdisplay window) or at the host processor (Business
Continuity Manager Pairdisplay command).
A volume which is not assigned to a URz data volume pair has the status simplex. When a URz data
volume pair is started, the primary storage system changes the status of the primary data volume and
secondary data volume to pending duplex. When the initial copy operation is complete, the primary
storage system changes the status of both data volumes to duplex. When a pair is suspended from the
primary storage system, the primary storage system changes the status of the primary data volume and
Hitachi Universal Replicator for z/OS user guide for XP12000/XP10000 Disk Arrays and SVS 200
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