Introduction
When using an Oracle standby database for Business Continuity purposes there are 3 possible modes of
operation for determining how the data is sent from the primary (the database currently being used to
support the business queries) database to the standby (fail over database to be used upon invocation of business continuity) database.
1-Maximum Performance
2-Maximum Protection
3-Maximum Availability
1-Maximum Performance Mode---
This performance mode provides the highest level of data protection that is possible without affecting the performance of a primary database.
This is accomplished by allowing transactions to commit as soon as all redo data generated by those transactions has been written to the on line log.
Redo data is also written to one or more standby databases, but this is done asynchronously with respect to transaction commitment,
so primary database performance is unaffected by delays in writing redo data to the standby database(s).
This protection mode offers slightly less data protection than maximum availability mode and has minimal impact on primary database performance.
This is the default protection mode.
2-Maximum Protection
This protection mode guarantees that no data loss will occur if the primary database fails.
To provide this level of protection, the redo data needed to recover each transaction must be written to both the local online redo log and
to the standby redo log on at least one standby database before the transaction commits. To ensure data loss cannot occur, the primary database
shuts down if a fault prevents it from writing its redo stream to at least one remote standby redo log.
3- Maximum Availability
This protection mode provides the highest level of data protection that is possible without compromising the availability of a primary database.
Transactions do not commit until all redo data needed to recover those transactions has been written to the online redo log and to at least one
synchronized standby database.
This mode ensures that no data loss will occur if the primary database fails, but only if a second fault does not prevent a complete set of redo data from being sent from the primary database to at least one standby database
When using an Oracle standby database for Business Continuity purposes there are 3 possible modes of
operation for determining how the data is sent from the primary (the database currently being used to
support the business queries) database to the standby (fail over database to be used upon invocation of business continuity) database.
1-Maximum Performance
2-Maximum Protection
3-Maximum Availability
1-Maximum Performance Mode---
This performance mode provides the highest level of data protection that is possible without affecting the performance of a primary database.
This is accomplished by allowing transactions to commit as soon as all redo data generated by those transactions has been written to the on line log.
Redo data is also written to one or more standby databases, but this is done asynchronously with respect to transaction commitment,
so primary database performance is unaffected by delays in writing redo data to the standby database(s).
This protection mode offers slightly less data protection than maximum availability mode and has minimal impact on primary database performance.
This is the default protection mode.
2-Maximum Protection
This protection mode guarantees that no data loss will occur if the primary database fails.
To provide this level of protection, the redo data needed to recover each transaction must be written to both the local online redo log and
to the standby redo log on at least one standby database before the transaction commits. To ensure data loss cannot occur, the primary database
shuts down if a fault prevents it from writing its redo stream to at least one remote standby redo log.
3- Maximum Availability
This protection mode provides the highest level of data protection that is possible without compromising the availability of a primary database.
Transactions do not commit until all redo data needed to recover those transactions has been written to the online redo log and to at least one
synchronized standby database.
This mode ensures that no data loss will occur if the primary database fails, but only if a second fault does not prevent a complete set of redo data from being sent from the primary database to at least one standby database
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