這是前段時間遇到的，今天有時間把它記錄下來。

情況是這樣的，使用者的OracleRAC叢集機房沒有安裝UPS，而且供電不穩定，因此總是突然斷電，前面幾次還可以，供電後集群就自動恢復了，但到最後還是出問題了，現象就是例項啟動不了。

經過幾次恢復，發現大概可以分為以下幾種情況，現分別描述如下。

情況一：可直接從redo日誌中恢復

[[email protected] ~]$ sqlplus / as sysdba

SQL*Plus: Release 11.2.0.4.0 Production on Mon Jul 11 10:29:04 2016

Copyright (c) 1982, 2013
 
, Oracle.  All rights reserved.

Connected to an idle instance.

SQL> startup mount
ORACLE instance started.

Total System Global Area 1.0796E+11 bytes
Fixed Size                  2266024 bytes
Variable Size            5.9861E+10 bytes
Database Buffers         4.8050E+10 bytes
Redo Buffers               50450432
 
 bytes
Database mounted.
SQL> alter database open;
alter database open
*
ERROR at line 1:
ORA-00600: internal error code, arguments: [kcrfr_read_5], [63], [674817], [],
[], [], [], [], [], [], [], []

此時的情況是例項無法開啟，報600錯誤，其實就是有操作日誌沒有commit成功，查詢一下當前的日誌情況

SQL> select group#,sequence#,status,first_time,next_change# from v$log;

    GROUP
 
#  SEQUENCE# STATUS                           FIRST_TIME   NEXT_CHANGE#
---------- ---------- -------------------------------- ------------ ------------
         5         63 CURRENT                          28-MAY-16      2.8147E+14
         2         62 INACTIVE                         25-MAY-16        22437896
         1         61 INACTIVE                         22-MAY-16        21890487
         4         68 INACTIVE                         24-MAY-16        22317178
         6         69 CURRENT                          27-MAY-16      2.8147E+14
         3         67 INACTIVE                         21-MAY-16        21837803

6 rows selected.

OK，是Group5的時間最新，然後到ASM中去查一下group5日誌檔案的具體路徑，在恢復的時候需要手工輸入。

[grid@db01 ~]$ asmcmd
ASMCMD> ls DATA/例項名/ONLINELOG/
group_1.261.898205699
group_2.262.898205705
group_3.267.898205911
group_4.268.898205917
group_5.263.898205713
group_6.269.898205925

好，用查到的日誌來恢復資料吧！

SQL> recover database until cancel using backup controlfile;
ORA-00279: change 22771825 generated at 05/30/2016 11:21:44 needed for thread 2
ORA-00289: suggestion : /work/11.2.0.4/oracle/db/dbs/arch2_69_898205698.dbf
ORA-00280: change 22771825 for thread 2 is in sequence #69

Specify log: {<RET>=suggested | filename | AUTO | CANCEL}
+DATA/例項名/ONLINELOG/group_5.263.898205713
Log applied.
Media recovery complete.

運氣不錯，日誌只是沒有commit，而不是損壞丟失，然後就可以open例項了，記得帶上resetlogs引數。

SQL> alter database open resetlogs;

Database altered.

SQL> quit
Disconnected from Oracle Database 11g Enterprise Edition Release 11.2.0.4.0 - 64bit Production
With the Partitioning, Real Application Clusters, Automatic Storage Management, Oracle Label Security,
OLAP, Data Mining, Oracle Database Vault and Real Application Testing options

例項能夠啟動後，還需要使用叢集命令來檢查一下狀態，不行的話，還可以重新用叢集命令啟動一下

crs_stat –t
srvctl start database -d 例項名

今天先到這裡，下次繼續講如果日誌損壞丟失情況下如何恢復。