FAST SYNC (SYNC NOAFFIRM) :
FAST SYNC is a new Data guard feature introduced in Oracle 12cR1 and it's required Oracle Active Data Guard(ADG) license to use for production.
Maximum Availability mode now allows the LOG_ARCHIVE_DEST_n attributes SYNC and NOAFFIRM to be used together for redo transport service. This enables asynchronous standby database to be deployed at a farther distance from the primary site without increasing the impact on primary DB performance.
The attribute NOAFFIRM in LOG_ARCHIVE_DEST_n parameter instructs the standby to acknowledge the receipt of redo changes without waiting for the Remote File Server (RFS) to write to a Standby Redo Logs (SRL).
This mode is only available in maximum availability protection mode.
example of SYNC NOAFFIRM attribute in LOG_ARCHIVE_DEST_n param on primary DB:
SQL> show parameter log_archive_dest_2
NAME TYPE VALUE
------------------------------------ ----------- ------------------------------
log_archive_dest_2 string service="STNDBYDB", SYNC NOAFFIRM
delay=0 optional compression=
disable max_failure=0 max_conn
ections=1 reopen=300 db_unique
_name="PRIMEDB" net_timeout=30,
valid_for=(online_logfile,all_
roles)
References:
https://oracleagent.wordpress.com/2021/12/08/data-guard-architecture/