How Thin Image pair status changes

The Thin Image pair status changes as you create, split, or perform other pair tasks.

The following figure illustrates status changes to Thin Image and snapshot pairs.

The following workflow describes the Thin Image pair status changes:

1. You choose two volumes that are in SMPL status and are not in use as a Thin Image pair.
2. You create a pair.

   If the primary volume has not previously been paired with any secondary volume, the pair status changes to "COPY" at first, and then to "PAIR" after the pair creation finishes.

   • Creation of a Thin Image pair may be time consuming if you create a pair immediately after deleting the last snapshot data for the primary volume.
   • If the pool threshold is exceeded when the Thin Image pair is in "PAIR" status, the pair status changes to "PFUL."
   • Thin Image pairs cannot be created when the pool threshold (warning threshold when snapshot data is stored in a DP pool) is exceeded or the pool is full.
3. Snapshot data is stored when you split a pair in "PAIR" status.

   After snapshot data is stored, the pair status is "PSUS." If the pool Warning threshold is exceeded when the Thin Image pair is in "PSUS" status, the pair status changes to "PFUS."

4. If you only want to delete snapshot data but do not want to release the Thin Image pair, you delete the snapshot data for the pair in "PSUS" or "PFUS" status.
5. If you restore a Thin Image pair in "PSUS" status, snapshot data is overwritten to the primary volume.

   The pair status is "COPY(RS-R) or RCPY" when the restore process is in progress. The pair status is "PAIR" after the restore process finishes.

6. The pool can only contain data of predetermined capacity.

   If the total capacity of snapshot data in the pool exceeds the pool capacity, the status of the Thin Image pair becomes "PSUE." In addition, the pair status changes to "PSUE" if a failure occurs during the restore process or if the pool usage rate reaches 100 percent. Even if the restore process is not in progress, the pair status may change to "PSUE" when a failure occurs. When snapshot data is stored in the DP pool, the timing of changing to PSUE is determined by the setting in "Suspend TI pairs when the deletion threshold is exceeded" in HDvM - SN, or by the setting specified by using the raidcom modify pool -suspend_tipair <yes|no> command in CCI. For details, see the Provisioning Guide for your storage system.