If there are no I/Os issued to the failure location, the GAD pair might not be suspended and remain in the same status as before the failure. The following procedures assume that there are I/Os issued to the failure location.
The following table lists the pair status (in the upper row) and I/O mode (in the lower row) in phases 1 to 6 of a failure occurrence during data migration.
| Phase of failure occurrence | Volume | Source GAD pair | Temporary GAD pair created for migration | Target GAD pair | |||
|---|---|---|---|---|---|---|---|
| Before the failure | After the failure | Before the failure | After the failure | Before the failure | After the failure | ||
| 1. Creating a temporary GAD pair | P-VOL | PAIR Mirror(RL) | No change | COPY Mirror(RL) | No change | ||
| S-VOL | PAIR Mirror(RL) | No change | COPY Block | No change | |||
| 2. Creating a target GAD pair | P-VOL | PAIR Mirror(RL) | No change | COPY Mirror(RL) | No change | COPY Mirror(RL) | No change |
| S-VOL | PAIR Mirror(RL) | No change | COPY Block | No change | COPY Block | No change | |
| 3. Suspending the source GAD pair (at the P-VOL) | P-VOL | PSUS Local | No change | COPY Mirror(RL) | No change | COPY Mirror(RL) | No change |
| S-VOL | SSUS Block | No change | COPY Block | No change | COPY Block | No change | |
| 4. The temporary GAD pair is migrated to PAIR | P-VOL | PSUS Local | No change | PAIR Mirror(RL) | PSUE2 Local | COPY Mirror(RL) | No change |
| S-VOL | SSUS Block | No change | PAIR Mirror(RL) | PSUE2 Block | COPY Block | No change | |
| 5. Suspending the temporary GAD pair (at the S-VOL) | P-VOL | PSUS Local | No change | PSUS Block | No change | COPY Mirror(RL) | No change1 |
| S-VOL | SSUS Block | No change | SSWS Local | No change | COPY Block | No change1 | |
| 6. The target GAD pair is migrated to PAIR | P-VOL | PSUS Local | No change | PSUS Block | No change | PAIR Mirror(RL) | No change |
| S-VOL | SSUS Block | No change | SSWS Local | No change | PAIR Mirror(RL) | No change | |
Notes:
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