LOG_SIMULTANEOUS_COPIES specifies the maximum number of redo buffer copy latches available to write log entries simultaneously. For good performance, you can have up to twice as many redo copy latches as CPUs. For a single-processor system, set to zero so that all log entries are copied on the redo allocation latch
In Oracle,if a process wants to write anything into the SGA it has to acquire a latch.So if LGWR wants to write to redo log files it has to acquire a latch so that no other process makes changes to that part when it is copying.
In case of any help please be free to write to me at email@example.com