Chapter 5. Extended Remote Copy 223
SDM copies data in real time, so it constantly transfers updated records from perhaps
multiple LCUs in an XRC session. In our example, we simulate moving the
clock forward in
time and tracing the steps taken by SDM in the production of its second CG.
Notice that LCU(A) and LCU(B) at the primary site now have different times indicating when
SDM reads the updated records. We proceed as before:
SDM reads from LCU(A) at 10:35:
At 10:35, SDM reads three records from LCU(A) (10:27, 10:31, and 10:35). Note that the
log update (10:27) has now been read. This group of three records has been designated
GRP1 in the diagram.
SDM reads from LCU(B) at 10:36:
At 10:36, SDM reads one record from LCU B (10:29). This record ...