Hitachi MP-96RD625-01 Manual de usuario descargar pdf (Pagina 124)

3-58 Chapter 3 Preparing for Universal Replicator z/OS Operations

Hitachi Universal Replicator for IBM /OS User’s Guide

Data transfer speed

between hosts and

the MCU

Data transfer speed of journal volumes

Data transfer speed

between the MCU and the RCU

Time

Normal status

Temporary increase in

data to be transferred

Data transfer

speed

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, V

H-M

is the data transfer speed between hosts and the primary

storage system. V

M-R

is the data transfer speed between the primary storage

system and the secondary storage system. t is the length of time during which

data transfer can continue.

Journal volume capacity > V

H-M

- V

M-R

× t

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 V

M-R

The total capacity of journal volumes in each journal group must exceed the

value illustrated above.

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Hitachi MP-96RD625-01 Manual de usuario Pagina 124