What do dataguard protection modes do?

Dataguard protection modes implement certain rules. These rules govern how the configuration will respond to failures.This helps us achieve our specific objectives for data protection,availability, performance

Do all standby databases have similar or different protection mode setting?

In a dataguard setup, a primary database can have more than one standby database configured for protecting its dats.These standby databases can have similar or different dataguard protection modes setup for them depending on the requirements.To brief it, dataguard protection modes setup for standby databases can be different.

What are the different dataguard protection modes?

There are three major dataguard protection modes :

1) Maximum Performance

2) Maximum Availability

3) Maximum Protection

1) Maximum Performance - Greater emphasis on database performance over protection. So primary database's LGWR process can't be waiting for acknowledgement from standby database.

2) Performance and availability of primary database should not be affected by :

     1) Redo transport

     2) Status of network connection between primary and secondary

     3) Availability of standby database

3) From Oracle dataguard 11g onwards, ASYNC(Asynchronous redo transport) has been default redo transport method for maximum performance

4) In previous dataguard releases, ARCH transport had been default redo transport method

5) ASYNC  has better data protection compared to ARCH

1) Maximum Availability - First priority is database availability, second priority is zero data loss

2) SYNC reo transport is needed - though there may be performance impact, it guarantees zero data loss and high availability

3) Primary database will have NET_TIMEOUT=a seconds configured. Once NET_TIMEOUT seconds expire, LGWR process disconnects its connection with the LNS process ar primary site,acknowledges commit and proceeds.Primary database waits for a seconds before giving up on the standby destination and allowing primary database processing to proceed inspite of communication loss between primary and secondary

4) Dataguard will automatically resynchronize with the standby database, once connection is reestablished between primary and secondary

1) Maximum protection - Emphasis on data protection, zero data loss

2) SYNC (Synchronous) redo transport mechanism is employed

3) LGWR process in primary database waits for acknowledgement from LNS process in primary database to commit user transactions

4) Database performance is compromised in this mode against zero data loss