OBSERVER

OBSERVER;
==========

1 observe is implemented on different server apart from primary and standby
2 Observers job is to maintain a connection with primary and the target standby
  monitoring the health of the configuration and performing th failover when required
3 The observer is also responsible for performing the automatic resinstatement of the failed primary database
  when it comes backonline ,if possible
4 observer is availble with oracle client, which of same or higher of database
5 the observer should be able to communicate with primary and standby database vi tnsnames.ora


FSFO will happen when the following conditions are met
1) Observer is not able to communicate with primary , but able to communicate with standby
2) Primary and standby database are not able to communicate with each other
3) Observer is not able to reconnect with primary in specified period of 'FastStartFailoverThreshold'
4) Any of fast start failover conditions met as specified in broker

condition for FSFO
. Datfile offline ===> primary data file is offline due to write errot
. Corrupted Controlfile: The Primary controlfile is corrupted
. Corrupted Dictionary: A critic dictionory object in primary database is corrupted
. Inaccesible logfile : the LGWR is unable to write to any member of an online redo log group due to an I/O error
. Stuck Archiver : A primary ARCH process is unable to to archive an online redo log because the archive log destination is full or unavailable


we can enable the FSFO condition via broker
DGMGRL>FAST_START FAILOVER CONDITION "Corrupted Controlfile";

We can also enter ORA error condition generated by the primary

DGMGRL>ENABLE FAST_START FAILOVER CONDITION 27102;

. Current setting of FSFO conditions can be obtained by the following command
DGMGRL>SHOW FAST_START FAILOVER


ENABLING FAST-START FAILOVER 
meet all  prerquiestes

Enable flasbback Database on both primary and standby
Setup the configuration correctly for the protection moe 11g supports 
max availablity and maxperformance protection modes
standby redo log files on both sides
redo transport setup the same in both directions
install the Observer system and configure TNSNAMES

The observer should be Installed in separate machine othe than of the primary and standby 





green primary
red standby

dgmgrl
DGMGRL>connect sys/india123
DGMGRL>show configuration

DGMGRL>show configuration
DGMGRL>edit database standby set state='APPLY-OFF';
DGMGRL>show configuration

DGMGRL>show fast_start failover
DGMGRL>edit database standby set state='APPLY-OFF';
DGMGRL>show database verbose primary
DGMGRL>show database verbose standby
DGMGRL>edit database primary set property  FastStartFailoverTarget='standby';
DGMGRL>edit configration SET PROPERTY FastStartFailoverThreshold=45;
DGMGRL>show Fast_Start Failover;
DGMGRL>enable Fast_start failover;
DGMGRL>show configuration
DGMGRL>edit database standby set state='APPLY-ON';
DGMGRL>show configuratioN
DGMGRL>show configuratioconnect sys/india123
DGMGRL>connect sys/india123@primary
DGMGRL>start observer file='/tmp/observer.dat';