Tow locations, one locate, one remote. Note the two destinations in this sample setup :
Q 1: Does the archiver writes to local (primary) and also on remote (standby) parallely..?
log_archive_dest_1='LOCATION=USE_DB_RECOVERY_FILE_DEST VALID_FOR=(ALL_LOGFILES,ALL_ROLES) DB_UNIQUE_NAME=PRIMARY' log_archive_dest_2='SERVICE=STANDBY LGWR ASYNC VALID_FOR=(ONLINE_LOGFILES,PRIMARY_ROLE) DB_UNIQUE_NAME=STANDBY'
Normally it will start sending redo again and catch up. Sometimes you may have to restart MRP on the standby to kick start it.
What if standby archive destination is 'defered' for 2 hours and again 'enabled'..?