You should understand the relationship between the GAD status, pair status, and I/O mode to be informed about your GAD pairs.
The following table lists the GAD statuses and describes the relationship between the GAD status, pair status, and I/O mode. "N" indicates that pair status or I/O mode cannot be identified due to a failure in the storage system.
| GAD status | When to suspend | P-VOL | S-VOL | Volume that has the latest data | ||
|---|---|---|---|---|---|---|
| Pair status | I/O mode | Pair status | I/O mode | |||
|
Simplex |
Not applicable |
SMPL |
Not applicable |
SMPL |
Not applicable |
Not applicable |
|
Mirroring |
Not applicable |
INIT |
Mirror(RL) |
INIT |
Block |
P-VOL |
|
Not applicable |
COPY |
Mirror(RL) |
COPY |
Block |
P-VOL |
|
|
Mirrored |
Not applicable |
PAIR |
Mirror(RL) |
PAIR |
Mirror(RL) |
P-VOL and S-VOL |
|
Quorum disk blocked or no quorum disk volume |
Not applicable |
PAIR |
Mirror(RL) |
PAIR |
Mirror(RL) |
P-VOL and S-VOL |
|
Suspended |
Pair operation |
PSUS |
Local |
SSUS |
Block |
P-VOL |
|
Failure |
PSUE* |
Local |
PSUE |
Block |
P-VOL |
|
|
PSUE* |
Local |
SMPL |
Not applicable |
P-VOL |
||
|
PSUE* |
Local |
N |
N |
P-VOL |
||
|
Pair operation |
PSUS |
Block |
SSWS |
Local |
S-VOL |
|
|
Failure |
PSUE |
Block |
SSWS* |
Local |
S-VOL |
|
|
SMPL |
Not applicable |
SSWS* |
Local |
S-VOL |
||
|
N |
N |
SSWS* |
Local |
S-VOL |
||
|
Blocked |
Not applicable |
PSUE |
Block |
PSUE |
Block |
P-VOL and S-VOL |
|
Not applicable |
PSUE |
Block |
N |
N |
P-VOL and S-VOL |
|
|
Not applicable |
N |
N |
PSUE |
Block |
P-VOL and S-VOL |
|
|
*: If the server does not issue the write I/O, the pair status might be PAIR, depending on the failure location. |
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