HP XP Racks - Manual (Page 11)

When the host issues an update after the initial copy is complete, the data is written to the P-VOL
and copied to the S-VOL. Subsequent updates are held until the current update is completed in
both volumes. This keeps the pair synchronized.
Pair status
The pair status is managed by the primary storage system which manages the P-VOLs.
•
The primary storage system is able to change the pair status of the P-VOL and the S-VOL.
•
The secondary storage system can change the pair status of the S-VOLs, but cannot change
the pair status of the P-VOLs. The primary storage system detects the change of the pair status
of S-VOL, and then change the status of P-VOL.
•
The pair status changes as follows:
◦ If the volume is not assigned to the Continuous Access Synchronous pair, the volume
status is SMPL.
◦ When the initial copy begins to create a pair, the primary storage system changes the
status of both volumes to COPY (volumes to be copying). When the initial copy completes,
the primary storage system changes the status of both volumes to PAIR (volumes become
a pair).
◦ When user splits the pair from the primary storage system or the secondary storage
system, the status of the P-VOL and the S-VOL are changed to PSUS (pair suspended-split:
split by a command).
◦ The primary storage system cannot keep the synchronisation of the P-VOL and the S-VOL
by some reasons, for example errors, the primary storage system changes the status of
the P-VOL and the S-VOL to PSUE (pair suspended-error: split by an error).
◦ When the user removes the pair from the primary storage system, the primary storage
system changes the status of the P-VOL and the S-VOL to SMPL.
◦ When the user removes the pair from the secondary storage system, the secondary storage
system changes the status of the S-VOL to SMPL, and then the primary storage system
detects the removal of the pair at the secondary system (if the path is normal), the primary
storage system changes the status of the P-VOL to PSUS.
Pair status 11