操作系统环境：
[root@rac-db2 ~]# cat /etc/oracle-release
Oracle Linux Server release 6.3
[root@rac-db2 ~]# cat /etc/redhat-release
Red Hat Enterprise Linux Server release 6.3 (Santiago)
[root@rac-db2 ~]# uname -a
Linux rac-db2 2.6.39-200.24.1.el6uek.x86_64 #1 SMP Sat Jun 23 02:39:07 EDT 2012 x86_64 x86_64 x86_64 GNU/Linux
[root@rac-db2 ~]#
机器上面使用的磁盘：
[root@rac-db2 ~]# fdisk -l
Disk /dev/sda: 42.9 GB, 42949672960 bytes
255 heads, 63 sectors/track, 5221 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disk identifier: 0x00081b38
Device Boot Start End Blocks Id System
/dev/sda1 * 1 5100 40960000 83 Linux
/dev/sda2 5100 5222 982016 82 Linux swap / Solaris
Disk /dev/sdb: 1073 MB, 1073741824 bytes
255 heads, 63 sectors/track, 130 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disk identifier: 0x4af1bcf1
Device Boot Start End Blocks Id System
Disk /dev/sdc: 1073 MB, 1073741824 bytes
255 heads, 63 sectors/track, 130 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disk identifier: 0x45528f9a
Device Boot Start End Blocks Id System
Disk /dev/sdd: 1073 MB, 1073741824 bytes
255 heads, 63 sectors/track, 130 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disk identifier: 0xf65dbdac
Device Boot Start End Blocks Id System
Disk /dev/sde: 1073 MB, 1073741824 bytes
255 heads, 63 sectors/track, 130 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disk identifier: 0xe0e7f25c
Device Boot Start End Blocks Id System
Disk /dev/sdf: 1073 MB, 1073741824 bytes
255 heads, 63 sectors/track, 130 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disk identifier: 0x4b720782
Device Boot Start End Blocks Id System
其中sdb sdc sdd sde sdf是给oracle asm使用的磁盘
下面是配置udev的过程：
1、得到每个磁盘对应的scsi id号，使用命令如下：
[root@rac-db1 ~]# scsi_id -g -u /dev/sdb
36000c29a982d7d5fe0af684b22046b34
[root@rac-db1 ~]# scsi_id -g -u /dev/sdc
36000c294085e61228085d870db2173af
[root@rac-db1 ~]# scsi_id -g -u /dev/sdd
36000c29a1a053b53514c7202e9fd2658
[root@rac-db1 ~]# scsi_id -g -u /dev/sde
36000c29ffa47abfd932ddf3a2f598633
[root@rac-db1 ~]# scsi_id -g -u /dev/sdf
36000c292926acffd78b0a49f27d62c51
2、编辑udev的配置文件
编辑文件/etc/udev/rules.d/99-oracle-asmdevices.rules，内容如下：
KERNEL=="sd*", BUS=="scsi", PROGRAM=="/sbin/scsi_id -g -u -s %p", RESULT=="36000c29a982d7d5fe0af684b22046b34", NAME="asmgrid_disk1", OWNER="grid", GROUP="asmadmin", MODE="0660"
KERNEL=="sd*", BUS=="scsi", PROGRAM=="/sbin/scsi_id -g -u -s %p", RESULT=="36000c294085e61228085d870db2173af", NAME="asmgrid_disk2", OWNER="grid", GROUP="asmadmin", MODE="0660"
KERNEL=="sd*", BUS=="scsi", PROGRAM=="/sbin/scsi_id -g -u -s %p", RESULT=="36000c29a1a053b53514c7202e9fd2658", NAME="asmgrid_disk3", OWNER="grid", GROUP="asmadmin", MODE="0660"
KERNEL=="sd*", BUS=="scsi", PROGRAM=="/sbin/scsi_id -g -u -s %p", RESULT=="36000c29ffa47abfd932ddf3a2f598633", NAME="asmgrid_disk4", OWNER="grid", GROUP="asmadmin", MODE="0660"
KERNEL=="sd*", BUS=="scsi", PROGRAM=="/sbin/scsi_id -g -u -s %p", RESULT=="36000c292926acffd78b0a49f27d62c51", NAME="asmgrid_disk5", OWNER="grid", GROUP="asmadmin", MODE="0660"
3、加载配置文件
[root@rac-db1 /]# udevadm control reload-rules
4、重启udev服务
[root@rac-db1 /]# start_udev
Starting udev: [ OK ]
5、检查配置结果
[root@rac-db1 /]# ls -l /dev/asm*
brw-rw---- 1 grid asmadmin 8, 16 Aug 31 11:11 /dev/asmgrid_disk1
brw-rw---- 1 grid asmadmin 8, 32 Aug 31 11:11 /dev/asmgrid_disk2
brw-rw---- 1 grid asmadmin 8, 48 Aug 31 11:11 /dev/asmgrid_disk3
brw-rw---- 1 grid asmadmin 8, 64 Aug 31 11:11 /dev/asmgrid_disk4
brw-rw---- 1 grid asmadmin 8, 80 Aug 31 11:11 /dev/asmgrid_disk5
[root@rac-db1 proc]# udevadm info --query=all --path=/block/sdc
P: /devices/pci0000:00/0000:00:11.0/0000:02:05.0/host3/target3:0:1/3:0:1:0/block/sdc
N: asmgrid_disk2
W: 50
S: block/8:32
S: disk/by-id/scsi-36000c294085e61228085d870db2173af
S: disk/by-path/pci-0000:02:05.0-scsi-0:0:1:0
S: disk/by-id/wwn-0x6000c294085e61228085d870db2173af
E: UDEV_LOG=3
E: DEVPATH=/devices/pci0000:00/0000:00:11.0/0000:02:05.0/host3/target3:0:1/3:0:1:0/block/sdc
E: MAJOR=8
E: MINOR=32
E: DEVNAME=/dev/asmgrid_disk2
E: DEVTYPE=disk
E: SUBSYSTEM=block
E: ID_SCSI=1
E: ID_VENDOR=VMware
E: ID_VENDOR_ENC=VMware\x20\x20
E: ID_MODEL=Virtual_disk
E: ID_MODEL_ENC=Virtual\x20disk\x20\x20\x20\x20
E: ID_REVISION=1.0
E: ID_TYPE=disk
E: ID_SERIAL_RAW=36000c294085e61228085d870db2173af
E: ID_SERIAL=36000c294085e61228085d870db2173af
E: ID_SERIAL_SHORT=6000c294085e61228085d870db2173af
E: ID_WWN=0x6000c294085e6122
E: ID_WWN_VENDOR_EXTENSION=0x8085d870db2173af
E: ID_WWN_WITH_EXTENSION=0x6000c294085e61228085d870db2173af
E: ID_SCSI_SERIAL=6000c294085e61228085d870db2173af
E: ID_BUS=scsi
E: ID_PATH=pci-0000:02:05.0-scsi-0:0:1:0
E: ID_PART_TABLE_TYPE=dos
E: LVM_SBIN_PATH=/sbin
E: UDISKS_PRESENTATION_NOPOLICY=0
E: UDISKS_PARTITION_TABLE=1
E: UDISKS_PARTITION_TABLE_SCHEME=mbr
E: UDISKS_PARTITION_TABLE_COUNT=0
E: DEVLINKS=/dev/block/8:32 /dev/disk/by-id/scsi-36000c294085e61228085d870db2173af /dev/disk/by-path/pci-0000:02:05.0-scsi-0:0:1:0 /dev/disk/by-id/wwn-0x6000c294085e61228085d870db2173af
[root@rac-db1 proc]#
配置了udev后，操作系统fdisk命令看不到asm使用的磁盘
[root@rac-db1 proc]# fdisk -l
Disk /dev/sda: 42.9 GB, 42949672960 bytes
255 heads, 63 sectors/track, 5221 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disk identifier: 0x000cc4c1
Device Boot Start End Blocks Id System
/dev/sda1 * 1 5100 40960000 83 Linux
/dev/sda2 5100 5222 982016 82 Linux swap / Solaris
对于rac中其他节点，把99-oracle-asmdevices.rules copy过去，再执行步骤3，4就可以了。