在CentOS 6.5上装rac，使用了multipath进行了多路径聚合，但是查看盘权限全部都是root用户，这时候需要再配置一下udev来保证磁盘权限的正确，属主和属组要改成grid，asmadmin，权限是660，如果不修改，之后添加asm磁盘会报错。具体添加步骤如下：
1.查看设备
[root@dzqd-rac2 ~]# dmsetup ls
data01 (253:2)
crs03 (253:3)
VG0-LV_ROOT (253:6)
crs02 (253:1)
crs01 (253:0)
data03 (253:5)
data02 (253:4)
2.配置udev规则
[root@oradbca ~]# cat /etc/udev/rules.d/12-dm-permissions.rules
ENV{DM_NAME}=="crs01", OWNER:="grid", GROUP:="asmadmin", MODE:="660", SYMLINK+="iscsi/oraasm-$env{DM_NAME}"
ENV{DM_NAME}=="crs02", OWNER:="grid", GROUP:="asmadmin", MODE:="660", SYMLINK+="iscsi/oraasm-$env{DM_NAME}"
ENV{DM_NAME}=="crs03", OWNER:="grid", GROUP:="asmadmin", MODE:="660", SYMLINK+="iscsi/oraasm-$env{DM_NAME}"
ENV{DM_NAME}=="data01", OWNER:="grid", GROUP:="asmadmin", MODE:="660", SYMLINK+="iscsi/oraasm-$env{DM_NAME}"
ENV{DM_NAME}=="data02", OWNER:="grid", GROUP:="asmadmin", MODE:="660", SYMLINK+="iscsi/oraasm-$env{DM_NAME}"
ENV{DM_NAME}=="data03", OWNER:="grid", GROUP:="asmadmin", MODE:="660", SYMLINK+="iscsi/oraasm-$env{DM_NAME}"
3.重启multipathd服务
service multipathd restart
4.核对权限是否已经成功变成grid,asmadmin 660
[root@oradbca ~]# ll /dev/dm-*
brw-rw---- 1 grid asmadmin 253, 0 Sep 13 14:18 /dev/dm-0
brw-rw---- 1 grid asmadmin 253, 1 Sep 13 14:18 /dev/dm-1
brw-rw---- 1 grid asmadmin 253, 2 Sep 13 14:18 /dev/dm-2
brw-rw---- 1 grid asmadmin 253, 3 Sep 13 14:18 /dev/dm-3
brw-rw---- 1 grid asmadmin 253, 4 Sep 13 14:18/dev/dm-4
brw-rw---- 1 grid asmadmin 253, 5 Sep 13 14:18 /dev/dm-5
brw-rw---- 1 root disk 253, 6 Sep 13 03:04 /dev/dm-6