Read requests are read by the P-VOL and then sent to the host. There is no
communication between the primary and secondary systems.
Related topics
•
Monitoring GAD status on page 1-10
•
Global-active device and server I/O on page 1-14
Server I/O when the GAD status is Suspended
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.
1-16
Overview of global-active device
Hitachi Virtual Storage Platform G1000 Global-Active Device User Guide
Summary of Contents for G1000
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Page 14: ...xiv Preface Hitachi Virtual Storage Platform G1000 Global Active Device User Guide ...
Page 238: ...9 18 Troubleshooting Hitachi Virtual Storage Platform G1000 Global Active Device User Guide ...
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