Hitachi ShadowImage for z/OS user guide (HIT9503-96009, January 2008)

Figure 17 Pair Status Transitions
1. If a volume is not assigned to a Siz pair (Siz pair), its status is simplex.
2. Select the simplex volumes for S-VOL and T-VOL to create a Siz pair. When you create a Siz
pair,
the initial copy operation starts. During the initial copy operation, the status of the S-VOL
and T-VOL changes to pending.
3. When the initial copy operation is complete, the pair status becomes duplex. When the
initi
al copy is completed, the differential data between the S-VOL and the T-VOL is copied
by the update copy.
4. There are two kinds of pair status (split and suspend) when the pair is not synchronized:
•When
you split a pair (pairsplit), the pair status changes to split. During the pairsplit process,
the p
air status becomes SP-pending. If you specify Quick Split pairsplit, the pair status
becomes V-Split during the process. When the split is complete, the pair status changes
to split, and you can access the split T-VOL. The update copy operation is not performed
on pairs where the status is split.
•Ift
he storage system cannot maintain duplex status for any reason, or if you suspend the
pair, the pair status changes to suspend.
5. When you start a pairresync operation, the pair status changes to resync or resync-r. When the
pa
irresync operation is complete, the pair status changes to PAIR.
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