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Data transfer |
speed |
Data transfer speed of journal volumes |
Data transfer speed |
between the MCU and the RCU |
Data transfer speed |
between hosts and |
the MCU |
Time |
Normal status | Temporary increase in |
| data to be transferred |
Figure 3-32 Data Transfer Speed with URz (Influence on Journal Volume Capacity)
The following factors determine the required journal volume capacity:
•the period of time during which data transfer can continue between hosts and the primary storage system when a temporary increase in transferred data occurs or when a communication path failure occurs between the primary and secondary storage system.
•the data transfer speed for the period of time that is mentioned above
To determine the journal volume capacity, use the following formula. In this formula,
Journal volume capacity >
If you want to calculate journal volume capacity that is required when a communication path failure occurs between the primary storage system and the secondary storage system, please assign 0 (zero) to
The total capacity of journal volumes in each journal group must exceed the value illustrated above.
Chapter 3 Preparing for Universal Replicator z/OS Operations |