HP StorageWorks XP Remote Web Console Software - Manual (Page 125)

TrueCopy for z/OS user guide 125
Deleting TrueCopy Volume Pairs (Delete Pair)
A TC390 pair should be deleted from the MCU only when it is no longer necessary to maintain a remote
copy of the M-VOL. When a TC390 volume pair is deleted from the MCU, the MCU stops all TC390 copy
operations for that pair and changes the pair status of the M-VOL and R-VOL to simplex. After a pair is
deleted, the MCU continues to accept all subsequent write I/O operations to the M-VOL and will not keep
track of the M-VOL updates.
A TC390 pair should be deleted from the RCU only if you need to access the R-VOL, such as to perform
ICKDSF on the R-VOL (see ” ICKDSF Considerations for TrueCopy Volumes ” on page 130) or for disaster
recovery (see ” TrueCopy Disaster Recovery Operations ” on page 134). When a TC390 volume pair is
deleted from the RCU, the RCU changes the R-VOL pair status to simplex, but does not change the pair
status of the corresponding M-VOL. When the MCU performs the next TC390 operation, the MCU detects
that the R-VOL status changed and changes the status of the M-VOL to suspended-delete pair to RCU.
When you delete a pair from the RCU to access the R-VOL, remember that the R-VOL and M-VOL have the
same VOLSER and take appropriate precautions to prevent a system problem due to duplicate VOLSERs.
To restart a pair that was deleted from the RCU, you must first delete the pair from the MCU, and then add
the pair from the MCU using the appropriate initial copy option (Entire or No Copy) to restart the pair.
You can delete all TC390 Synchronous pairs between an MCU and RCU (same CU image). You can also
delete all TC390A pairs in a consistency group by connecting to the MCU. The TC390A pair status will
change to deleting when the delete operation is accepted by the MCU and RCU, and then to simplex after
the internal delete pair process is complete. In addition, you can delete TC390A pairs according to their
consistency status (for example, for disaster recovery) by connecting to the RCU (the RCU maintains the
consistency status).
NOTE: The CDELPAIR TSO command can be used to delete TC390 pairs and TC390A groups of pairs
from the MCU (see ” Using PPRC Commands for TrueCopy ” on page 147).
CAUTION: For information about duplicate VOLSERs, see the caution in ” Duplicate VOLSER ” on
page 45.
As a general rule, when you want to delete a TC390A pair from the MCU, it is strongly recommended that
you perform the Delete Pair operation after the update copy operation is completed. If you demand the
Delete Pair operation while the update copy process is still in progress, it will take a long time to complete
the Delete Pair operation. However, when you urgently need to delete a TC390A pair, you can perform the
Delete Pair operation from the RCU. In this case, you will find the suspended status at the MCU after the
Delete Pair operation from the RCU.