NEC IS015-9E Chapter 2 Data Replication

Chapter 2 Data Replication

Copy control states can be specified when Replicate or Restore is performed. You can also change the

copy control state you specified at Replicate or Restore as required.

When Restore with RV protection specified is executed, only copy for reflecting the difference is

executed, thus the updated data of the MV is not reflected into the RV. Therefore, specifying or

changing a copy control state (Synchronous Copy Mode, Semi-synchronous Copy Mode, or

Background Copy) has no effect.

There are the following five instructions to change the copy control state.

• Synchronous Copy instruction

• Semi-synchronous Copy instruction

• Resume instruction

• Background Copy instruction

• Suspend instruction

The Resume instruction changes Background Copy or Suspend to preceding Foreground Copy

(Synchronous Copy Mode, Semi-synchronous Copy Mode).

Figure 2-6 shows the state transition diagram of the copy control states.

Figure 2-6 State Transition Diagram of Copy Control State

Foreground Copy

Background

Copy Instruction

* Semi-synchronous Copy Mode

can be used only for a

RemoteDataReplication pair

Suspend Instruction

Background Copy Instruction

Suspend

Synchronous Copy or

Semi-synchronous

Copy or Resume

Synchronous Copy or

Semi-synchronous Copy

or Resume Instruction

Suspend Instruction

Background Copy

Semi-

synchronous

Mode*

Sync Copy

Mode

normal abnormal

Copy Fault