Flash Recovery Area Full

FLASH RECOVERY AREA FULL
 
Database startup fails:
ORA-16038: log one sequence 3144 cannot be archived
ORA-19809: limit exceeded for recovery files
ORA-00312 online log 1 thread 1 <path to redo log file>

Cause
Using the default Oracle-Suggested strategy as implemented by EM in Oracle10gR1
Retention policy changed from the default redundancy of 1 to recovery window of  15 days
When the retention policy is changed to recovery window or to a redundancy > 1, RMAN cannot satisfy the retention policy if there is only one copy of database and it is recovered to the latest point in time.  In order to satisfy the
retention policy, it keeps all the incrementals and archivelogs since database creation
Solution
1) Increase the parameter db_recovery_file_dest_size
     SQL> ALTER SYSTEM SET DB_RECOVERY_FILE_DEST_SIZE=4g SCOPE=BOTH;
2) Stop using the db_recovery_file_dest by unsetting the parameter. 
    (This assumes you never really wanted to use this option)
3. Backup and delete archivelogs
    RMAN> backup archivelog all delete input;
It is the dba's responsibility to ensure that the FRA size is sufficient to account for their retention policy.