ORACLE RAC中的日志文件较多，主要根据资源，进程划分，具体日志路径结构如下

linux系统的应用日志
/tmp/crsctl.5129

CRS日志
$ORA_CRS_HOME/log/主机名/alert主机名.log
ASM日志
/u01/app/oracle/admin/+ASM/bdump/alert_+ASM1.log
数据库日志
/u01/app/oracle/admin/RACDB/bdump/alert_RACDB1.log

cluster主要进程日志
/u01/app/oracle/crs/log/oms/crsd/crsd.log

/u01/app/oracle/crs/log/oms/cssd/ocssd.log

/u01/app/oracle/crs/log/oms/evmd/evmd.log

遇到问题应根据问题所处位置查看相应日志文件，进而判断具体问题。
例如 在启动RAC系统资源时报如下错误
[root@oms bin]# ./srvctl start nodeapps -n oms

PRKH-1010 : Unable to communicate with CRS services.
  [Communications Error(Native: prsr_initCLSS:[3])]

通过crsctl检查crs健康状态
[root@oms bin]# ./crsctl check crs
Failure 1 contacting CSS daemon
Cannot communicate with CRS
Cannot communicate with EVM
发现crs相关资源根本未启动，无法连接，这时无论从CRS日志，ASM日志还是cluster主要进程日志中是无法获取相应日志的，因为crs根本没有启动，相应日志也就不会产生，因此最先查看的日志应该是系统日志
[root@oms bin]# tail -f /tmp/crsctl.5129
Failed 3 to bind listening endpoint: (ADDRESS=(PROTOCOL=tcp)(HOST=oms-priv))
从系统日志中得知hosts文件中主机名被更改，更正hosts文件后，重启network服务
[root@oms bin]# service network restart
Shutting down interface eth0:                              [  OK  ]
Shutting down interface eth1:                              [  OK  ]
Shutting down loopback interface:                          [  OK  ]
Bringing up loopback interface:                            [  OK  ]
Bringing up interface eth0:                                [  OK  ]
Bringing up interface eth1:                                [  OK  ]
[root@oms bin]# ./crsctl check crs
CSS appears healthy
CRS appears healthy
EVM appears healthy
crs已启动