用裸盘做ASM，有两种方式：
1、安装3个asm包，之后进行配置和使用。这种方式很多操作系统不能识别，不建议使用此方式；
http://www.jb51.net/article/43527.htm
2、用udev配置文件，然后启动udev。6系统和7系统的udev启动方式不一样，需要注意。
 


配置磁盘时，本地磁盘和多路径磁盘的区别：
1、本地磁盘/etc/udev/rules.d/60-raw.rules，其中对应的磁盘用磁盘名称，例如/dev/sdb1
2、多路径磁盘/etc/udev/rules.d/99-oracle-asmdevice.rules，其中对应的磁盘为多路径对应的名称，例如下：
[root@rac2 rules.d]# cd /dev/mapper/
[root@rac2 mapper]# ll
total 0
lrwxrwxrwx 1 root root       7 Oct 22 03:49 centos-home -> ../dm-6
lrwxrwxrwx 1 root root       7 Oct 22 03:49 centos-root -> ../dm-1
lrwxrwxrwx 1 root root       7 Oct 22 03:49 centos-swap -> ../dm-0
crw------- 1 root root 10, 236 Oct 22 03:49 control
lrwxrwxrwx 1 root root       7 Oct 22 03:49 mpatha -> ../dm-2
lrwxrwxrwx 1 root root       7 Oct 22 03:49 mpathb -> ../dm-3
lrwxrwxrwx 1 root root       7 Oct 22 03:49 mpathc -> ../dm-4
lrwxrwxrwx 1 root root       7 Oct 22 03:49 mpathd -> ../dm-5
[root@rac2 mapper]# cd ../
[root@rac2 dev]# ll dm*
brw-rw---- 1 root disk 253, 0 Oct 22 03:49 dm-0
brw-rw---- 1 root disk 253, 1 Oct 22 03:49 dm-1
brw-rw---- 1 root disk 253, 2 Oct 22 03:49 dm-2
brw-rw---- 1 root disk 253, 3 Oct 22 03:49 dm-3
brw-rw---- 1 root disk 253, 4 Oct 22 03:49 dm-4
brw-rw---- 1 root disk 253, 5 Oct 22 03:49 dm-5
brw-rw---- 1 root disk 253, 6 Oct 22 03:49 dm-6
 
[root@rac2 rules.d]# cat 99-oracle-asmdevice.rules
ACTION=="add",KERNEL=="dm-2",RUN+="/bin/raw /dev/raw/raw1 %N"
ACTION=="add",ENV{MAJOR}=="8",ENV{MINOR}=="17",RUN+="/bin/raw /dev/raw/raw1 %M %m"
ACTION=="add",KERNEL=="dm-3",RUN+="/bin/raw /dev/raw/raw2 %N"
ACTION=="add",ENV{MAJOR}=="8",ENV{MINOR}=="33",RUN+="/bin/raw /dev/raw/raw2 %M %m"
ACTION=="add",KERNEL=="dm-4",RUN+="/bin/raw /dev/raw/raw3 %N"
ACTION=="add",ENV{MAJOR}=="8",ENV{MINOR}=="49",RUN+="/bin/raw /dev/raw/raw3 %M %m"
ACTION=="add",KERNEL=="dm-5",RUN+="/bin/raw /dev/raw/raw4 %N"
ACTION=="add",ENV{MAJOR}=="8",ENV{MINOR}=="65",RUN+="/bin/raw /dev/raw/raw4 %M %m"
KERNEL=="raw[1-4]",OWNER="grid",GROUP="dba",MODE="660"
 
重启udev
[root@rac2 rules.d]# systemctl restart systemd-udev-trigger.service
显示裸盘
[root@rac2 rules.d]# ll /dev/raw/
total 0
crw-rw---- 1 grid dba  162, 1 Oct 22 03:49 raw1
crw-rw---- 1 grid dba  162, 2 Oct 22 03:49 raw2
crw-rw---- 1 grid dba  162, 3 Oct 22 03:49 raw3
crw-rw---- 1 grid dba  162, 4 Oct 22 03:49 raw4
crw-rw---- 1 root disk 162, 0 Oct 22 03:49 rawctl
[root@rac2 rules.d]#
或者用命令执行，这个命令行写入99文件中
for i in dm-2 dm-3 dm-4 dm-5 fra; do
printf "%s %s\n" "$i" "$(udevadm info --query=all --name=/dev/mapper/$i |grep -i dm_uuid)"; done
 
然后重启udev
systemctl restart systemd-udev-trigger.service
 


附加内容：
centos7udev命令
systemctl restart systemd-udev-trigger.service已整合到UDEV后台服务中了．

systemd-udev-settle.service
loaded active exited udev Wait for Complete Device Initialization
systemd-udev-trigger.service loaded active exited    udev Coldplug all Devices
systemd-udevd.service loaded active running   udev Kernel Device Manager
systemd-udevd-control.socket loaded active running   udev Control Socket
systemd-udevd-kernel.socket loaded active running   udev Kernel Socket
 
 


多路径软件配置使用的校验命令：
multipath -ll | grep mpath
mpathe (360022a11000cb6b10a9116d000000002) dm-1 HUAWEI  ,S5500T
#下面是设备的详细信息
suse11a:~ # multipath -ll
#以下命令均可以用于校验多路径设备
# ll /dev/disk/by-id/
# ls -l /dev/dm-*
# ll /dev/mapper/
#/dev/dm-*下面的为动态名，即系统重启后会发生变化，此部分用于os 内部使用。
#/dev/mapper/下面查看到的内容为持久化名称，也即是我们在mulitpatch.conf文件中定义的。