Urz data volume 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
“Delta Resync Setting in 3DC Multi-target Configuration (After Failure Occurred)”
, 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
for Performing Delta Resync Operation” (page 81)
.
URz Data Volume Pair Status
URz displays the pair status for each data volume of specified CU Image (CUI) in the connected
XP storage system.
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 secondary data volume (if the path status is normal) to suspended. When
a pair is suspended from the secondary storage system, the secondary storage system changes
URz Data Volume Pair Status
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