HP XP P9500 Storage - Manual (Page 14)

resynchronized, the primary system merges the P-VOL and S-VOL bitmaps, and the differential data
is copied to the S-VOL.
The number of bitmap areas affects the maximum possible number of pairs that can be created in
the system.
S-VOL write option
When splitting a pair, you can set an option allowing write I/O to the S-VOL. When you
resynchronize a split pair whose S-VOL is write-enabled, the secondary system sends the S-VOL
track bitmap to the primary system, which merges the P-VOL and S-VOL bitmaps to determine which
tracks are out of sync. This ensures proper resynchronization of the pair.
Pair status
Every pair operation results in a change in pair status. In addition, when you want to perform an
operation, the pair must have a specific status in order to for the operation to run. You will monitor
pair status to ensure that you can perform the desired operation, and to ensure that an operation
completed successfully.
The following provides a brief description of the pair statuses. For complete details, see “Pair status
definitions” (page 66) .
•
SMPL: A volume that is not assigned to a pair is in simplex status, SMPL.
•
COPY: When copy processing is started, the primary system changes the status of the P-VOL
and S-VOL to COPY.
•
PAIR: When the initial copy processing is complete, the primary system changes the status of
both data volumes to PAIR.
•
PSUE: When a pair is suspended due to an error condition, the primary system changes the
P-VOL and S-VOL status to PSUE (if the path status is normal).
•
PSUS:
◦ When a pair is split by the user (pairsplit-r), the primary or secondary system changes
the status of the P-VOL and S-VOL to PSUS (if the path status is normal).
◦ If a pair is split from the secondary system, it changes the S-VOL status to PSUS. The
primary system detects the split (if path status is normal) and changes the P-VOL status to
PSUS.
14 Continuous Access Journal overview