Oracle Data Guard have different types to provide protection to Production’s critical data. That we can see as Protection Modes in Data Guard. There are three types of Protection Modes in Dataguard : - Maximum Availability - Maximum Performance - Maximum Protection. It provides highest level of protection to data without compromising availability of database. Once transaction’s redo data is transferred and written to standby redo log files then RFS process sent a acknowledgement to primary database and then that transaction commits at primary database. As its name says it provides maximum level of data protection that a database can have without compromising performance of database. This is default Protection mode in dataguard. This mode allows transactions to commit as soon as all redo data generated by those transactions are written to online redo log files. This mode offers less data protection than Maximum Availability mode. This protection mode ensures zero data loss if primary database fails. We have seen in Maximum Availability protection mode that if it cannot write to one of synchronized standby database it works as if it were in Maximum Performance mode.  But here in Maximum Protection mode , if database can not write to one of synchronized standby database , Primary database will shut down as this prioritize protection of primary database than availability of data.

Please Note : Oracle recommends when you use this mode of protection , you should keep at least two standby database that runs in maximum protection mode to prevent a single standby database failure from causing the primary database to shut down.