NEC M310 Configuration Manual page 73

5. Functions <Data Replication/Snapshot (3)>
Note:
The control information area in cache memory is used for differential management information. When
the control information area overflows, it is no longer possible to store all pair information in it. In this
case the replication reserved volume is also used. Information which is less frequently accessed is
stored on this volume in order to store more pair differential management information. The system also
writes information in this volume and reads from it. Because of this physical disk access, overall
performance may be degraded.
Host Director
Host Director
Cache Memory
Control Information Area
I/O Cache Area
Differential Management Info
Write Read
(Magnetic Disk) Logical Disk Replication Reserved Volume
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