客戶數據庫宕掉了，連接過去一看
可以正常到mount狀態，然後alter database open，觀察日誌裏面提示：
ORA-19809: limit exceeded for recovery files
Cause: The limit for recovery files specified by the DB_RECOVERY_FILE_DEST_SIZE was exceeded.
查詢官方對錯誤的處理方式如下：
http://docs.oracle.com/cd/E16655_01/server.121/e26079/e19500.htm
ORA-19809: limit exceeded for recovery files
Cause:The limit for recovery files specified by the DB_RECOVERY_FILE_DEST_SIZE was exceeded.
Action:There are five possible solutions:
1) Take frequent backup of recovery area using RMAN.
2) Consider changing RMAN retention policy.
3) Consider changing RMAN archived log deletion policy.
4) Add disk space and increase DB_RECOVERY_FILE_DEST_SIZE.
5) Delete files from recovery area using RMAN.
於是做如下操作：
crosscheck archivelog all;
直接刪除7天之前的歸檔日誌，騰出空間來
delete noprompt archivelog until time 'sysdate - 7';
現在sqlplus / as sysdba過去，正常啓動數據庫
SQL> select status from v$instance;
STATUS
------------
MOUNTED
SQL> alter database open;
SQL> select status from v$instance;
STATUS
------------
OPEN
後續處理，防止該問題頻繁發生：
RMAN> CONFIGURE RETENTION POLICY TO RECOVERY WINDOW OF 7 DAYS;
RMAN> CONFIGURE CONTROLFILE AUTOBACKUP ON;
SQL> alter system set db_recovery_file_dest_size=10G scope=both;
SQL> alter system set log_archive_dest_1='location=/opt/oracle/oradata/archive_log' scope=both;
現在切換日誌alter system archive log current;可以通過select name from v$archived_log;查看，看歸檔已經到了新路徑，也可去select name from v$archived_log;下檢查。
分析：導致該問題主要由於歸檔日誌在快速恢復區下，當快速恢復區被充滿的時候，則無法進行歸檔，所以導致數據庫宕機，處理方式即
（1）改變rman的策略，從而進行定期清理歸檔日誌。
（2）修改歸檔路徑，從而不受快速恢復區的影響
（3）修改db_recovery_file_dest_size大小