GAD pairs might be created between the primary and secondary sites that configure GAD as follows:
- A P-VOL of a GAD pair is at site 1 and a S-VOL is at site 2.
- A P-VOL of a different GAD pair is at site 2 and a S-VOL is at site 1.
In this case, recover from a physical path failure.
The following table shows transitions for pair status and I/O mode, the volumes that are accessible from the server, and the location of the latest data when you can no longer use the quorum disk volume.
|
Before failure |
After failure |
|||||
|---|---|---|---|---|---|---|
|
Pair status and I/O mode |
Pair status and I/O mode |
Volume accessible from the server |
Volume with latest data |
|||
|
P-VOL |
S-VOL |
P-VOL |
S-VOL |
P-VOL |
S-VOL |
|
|
PAIR (Mirror(RL)) |
PAIR (Mirror(RL)) |
PAIR (Mirror(RL)) |
PAIR (Mirror(RL)) |
OK |
OK |
Both P-VOL and S-VOL |
|
PAIR (Mirror (RL)) |
PAIR (Block) |
PAIR (Mirror(RL)) |
PAIR (Block) |
OK |
NG |
Both P-VOL and S-VOL |
|
COPY (Mirror(RL)) |
COPY (Block) |
COPY (Mirror(RL))* |
COPY (Block)* |
OK |
NG |
P-VOL |
|
PSUS/PSUE (Local) |
SSUS/PSUE (Block) |
PSUS/PSUE (Local) |
SSUS/PSUE (Block) |
OK |
NG |
P-VOL |
|
PSUS/PSUE (Block) |
SSWS (Local) |
PSUS/PSUE (Block) |
SSWS (Local) |
NG |
OK |
S-VOL |
|
The P-VOL might change to PSUE (Local) and the S-VOL might change to PSUE (Block) if a quorum disk failure occurred immediately after the pair status changed to COPY. |
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SIMs
- Primary storage system: 21D0xy, 21D2xx, DD2xyy, DEF0zz, EF5xyy, EFD000, FF5xyy
- Secondary storage system: 21D0xy, 21D2xx, DD2xyy, DEF0zz, EF5xyy, EFD000, FF5xyy