RAC在OCR磁碟故障且有備份時的恢複操作，racocr
問題描述：
CRS啟動失敗，並且RAC進程全部退出。
查看messages日誌：
... ...
Apr 10 15:58:31 node74 logger: Cluster Ready Services waiting on dependencies. Diagnostics in /tmp/crsctl.7510.
Apr 10 15:58:31 node74 logger: Cluster Ready Services waiting on dependencies. Diagnostics in /tmp/crsctl.7264.
Apr 10 15:58:31 node74 logger: Cluster Ready Services waiting on dependencies. Diagnostics in /tmp/crsctl.7174.
Apr 10 15:59:31 node74 su: (to oracle) root on none
Apr 10 15:59:31 node74 su: (to oracle) root on none
Apr 10 15:59:31 node74 su: (to oracle) root on none
Apr 10 15:59:31 node74 logger: Cluster Ready Services waiting on dependencies. Diagnostics in /tmp/crsctl.7510.
Apr 10 15:59:31 node74 logger: Cluster Ready Services waiting on dependencies. Diagnostics in /tmp/crsctl.7174.
Apr 10 15:59:31 node74 logger: Cluster Ready Services waiting on dependencies. Diagnostics in /tmp/crsctl.7264.
Apr 10 16:00:26 node74 su: (to oracle) root on /dev/pts/0
Apr 10 16:00:31 node74 su: (to oracle) root on none
Apr 10 16:00:31 node74 su: (to oracle) root on none
Apr 10 16:00:31 node74 su: (to oracle) root on none
Apr 10 16:00:31 node74 logger: Cluster Ready Services waiting on dependencies. Diagnostics in /tmp/crsctl.7264.
Apr 10 16:00:31 node74 logger: Cluster Ready Services waiting on dependencies. Diagnostics in /tmp/crsctl.7510.
Apr 10 16:00:31 node74 logger: Cluster Ready Services waiting on dependencies. Diagnostics in /tmp/crsctl.7174.
... ...
取其中一個檔案下來，/tmp/crsctl.7174：
Oracle Cluster Registry initialization failed with invalid format: PROC-22: The OCR backend has an invalid format
懷疑是OCR損壞。運行crsctl check boot命令，與上面的日誌報錯是一致的：
oracle@node74:~> crsctl check boot
Oracle Cluster Registry initialization failed with invalid format: PROC-22: The OCR backend has an invalid format
問題處理：
查看是否有OCR自動備份，很不幸，沒有結果輸出：
oracle@node74:~> ocrconfig -showbackup
---空
幸好之前做OCR遷移實驗時，有做過OCR的手動備份。
node74:/home/database/oracle/oracrs/bin # ll /home/oracle/ocr.exp
-rw-r--r-- 1 root root 87246 Dec 29 16:45 /home/oracle/ocr.exp
匯入之前備份的OCR：
node74:/home/database/oracle/oracrs/bin # ./ocrconfig -import /home/oracle/ocr.exp
檢查OCR：
node74:/home/database/oracle/oracrs/bin # ./ocrcheck
Status of Oracle Cluster Registry is as follows :
Version : 2
Total space (kbytes) : 975584
Used space (kbytes) : 3844
Available space (kbytes) : 971740
ID : 811637621
Device/File Name : /dev/raw/raw1
Device/File integrity check succeeded
Device/File not configured
Cluster registry integrity check succeeded
Logical corruption check succeeded
---修複成功
啟動CRS：
node74:/home/database/oracle/oracrs/bin # /etc/init.d/init.crs start
所有RAC進程啟動成功：
node74:~ # su - oracle
oracle@node74:~> crs_stat -t
Name Type Target State Host
------------------------------------------------------------
ora....SM1.asm application ONLINE ONLINE node74
ora....74.lsnr application ONLINE ONLINE node74
ora.node74.gsd application ONLINE ONLINE node74
ora.node74.ons application ONLINE ONLINE node74
ora.node74.vip application ONLINE ONLINE node74
ora....SM2.asm application ONLINE ONLINE node76
ora....76.lsnr application ONLINE ONLINE node76
ora.node76.gsd application ONLINE ONLINE node76
ora.node76.ons application ONLINE ONLINE node76
ora.node76.vip application ONLINE ONLINE node76
ora.orcl.db application ONLINE ONLINE node74
ora....l1.inst application ONLINE ONLINE node74
ora....l2.inst application ONLINE ONLINE node76
--問題解決
