When the GAD status is Suspended, the I/O mode differs depending on where the latest data is.
When the GAD status is Suspended and the latest data is on the P-VOL, the I/O mode is as follows:
- P-VOL: Local
- S-VOL: Block
When the latest data is on the S-VOL, the I/O mode is as follows:
- P-VOL: Block
- S-VOL: Local
When the latest data is on the P-VOL, write requests are written to the P-VOL, and then the write-completed response is returned to the host, as shown in the following figure. The S-VOL's I/O mode is Block, so it does not accept I/O from the server, and the P-VOL's I/O mode is Local, so the data written to the P-VOL is not written to the S-VOL.
Read requests are read by the P-VOL and then sent to the host. There is no communication between the primary and secondary storage systems.
