仅记录一次Oracle 11g rac安装过程.本文出自:http://koumm.blog.51cto.com/    
1. 采用RHEL6.5 multipath多路径软件安装采用udev方式配置ASM共享磁盘不成功，当时因为时间关系没有过多的分析与尝试。

OEL6.X IBM v3500存储多路径配置  
http://koumm.blog.51cto.com/703525/1439760

2. 采用RHEL6.5 multipath多路径软件安装采用ASMLIB方式配置ASM共享磁盘成功，但是在第二节点执 行root.sh报如下错误提示，解决方式见3.

Disk Group CRS creation failed with the following message:  
ORA-15018: diskgroup cannot be created    
ORA-15072: command requires at least 1 regular failure groups, discovered only 0    
ORA-15080: synchronous I/O operation to a disk failed

Configuration of ASM ... failed  
see asmca logs at /u01/app/grid/cfgtoollogs/asmca for details    
Did not succssfully configure and start ASM at  /u01/app/11.2.0/grid/crs/install/crsconfig_lib.pm line 6912.    
/u01/app/11.2.0/grid/perl/bin/perl -I/u01/app/11.2.0/grid/perl/lib - I/u01/app/11.2.0/grid/crs/install /u01/app/11.2.0/grid/crs/install/rootcrs.pl execution  failed

3. 解决方式如下

node1,node2 下：

# vi /etc/sysconfig/oracleasm

ORACLEASM_ENABLED=true  
ORACLEASM_UID=grid    
ORACLEASM_GID=asmdba    
ORACLEASM_SCANBOOT=true    
ORACLEASM_SCANORDER="dm"    
ORACLEASM_SCANEXCLUDE="sd"    
ORACLEASM_USE_LOGICAL_BLOCK_SIZE=false

# /etc/init.d/oracleasm restart

第二节点先执行清除配置，再执行root.sh即可:    
# /u01/app/11.2.0/grid/crs/install/roothas.pl -delete -force -verbose    
# /u01/app/11.2.0/grid/root.sh