问题描写：
CRS启动失败，并且RAC进程全部退出。
查看messages日志：
... ...
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1个文件下来，/tmp/crsctl.7174：
Oracle Cluster Registry initialization failed with invalid format: PROC⑵2: The OCR backend has an invalid format
怀疑是OCR破坏。运行crsctl check boot命令，与上面的日志报错是1致的：
oracle@node74:~> crsctl check boot
Oracle Cluster Registry initialization failed with invalid format: PROC⑵2: The OCR backend has an invalid format
问题处理：
查看是不是有OCR自动备份，很不幸，没有结果输出：
oracle@node74:~> ocrconfig -showbackup
---空
幸亏之前做OCR迁移实验时，有做过OCR的手动备份。
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
导入之前备份的OCR：
node74:/home/database/oracle/oracrs/bin # ./ocrconfig -import /home/oracle/ocr.exp
检查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
---修复成功
启动CRS：
node74:/home/database/oracle/oracrs/bin # /etc/init.d/init.crs start
所有RAC进程启动成功：
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
--问题解决