Dataguard configuration modification to MAXIMUM AVAILABILITY
In order to change the Dataguard configuration from MAXIMUM PERFORMANCE to MAXIMUM AVAILABILITY, Oracle doesn't require to bounce the databases anymore since 10.2.0.3.
In fact this is not always the case. The only way to verify if it will occur is:
1. change log transport mode
edit database 'MYDB_SITE1' set property LogXptMode = 'SYNC';
edit database 'MYDB_SITE2' set property LogXptMode = 'SYNC';
2. look for the following entry in the alert.log file of the PRIMARY database :
Destination LOG_ARCHIVE_DEST_2 is SYNCHRONIZED
If this string has been found, the Dataguard configuration can be changed smoothly (without database reboot) to MAXIMUM AVAILABILITY as described below :
edit configuration set protection mode as 'MaxAvailability';
Of course the standby redo log files must exist, see previous posts.
If the entry in the alert.log file has not been found a workaround could be to to set the LogXptMode property to 'ASYNC' and then back to 'SYNC'.
Many thanks to Hervé who was the first one to discover this by Trivadis 