You should understand the I/O actions on the P-VOL and the S-VOL of a GAD pair.
The following table lists and describes the GAD I/O modes. As shown in the following table, the I/O mode terms displayed by the user interfaces are slightly different.
| I/O mode |
Read processing |
Write processing | ||
|---|---|---|---|---|
| I/O mode | CCI 1 | Storage Navigator | ||
| Mirror (RL) | L/M | Mirror (Read Local) | Sends data from the storage system that received a read request to the server. | Writes data to the P-VOL and then the S-VOL. |
| Local | L/L | Local | Sends data from the storage system that received a read request to the server. | Writes data to the volume on the storage system that received a write request. |
| Block2 | B/B | Block | Rejected (Replies to illegal requests). | Rejected (Replies to illegal requests). |
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