Tuesday, December 31, 2019

What is the Fast Sync Oracle Data Guard feature?


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,


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