[grid@asmlnx2 ~]$ uname -a
Linux asmlnx2 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

[grid@asmlnx2 ~]$ cat /etc/*release*

Oracle Linux Server release 6.3
Red Hat Enterprise Linux Server release 6.3 (Santiago)
Oracle Linux Server release 6.3

[grid@asmlnx2 ~]$ ls -l  /dev/xvdv
brw-rw---- 1 root disk 202, 5376 Feb 11 21:31 /dev/xvdv

[root@asmlnx2 ~]#  fdisk  /dev/xvdv
Device contains neither a valid DOS partition table, nor Sun, SGI or OSF disklabel
Building a new DOS disklabel with disk identifier 0xba335ded.
Changes will remain in memory only, until you decide to write them.
After that, of course, the previous content won't be recoverable.

Warning: invalid flag 0x0000 of partition table 4 will be corrected by w(rite)

WARNING: DOS-compatible mode is deprecated. It's strongly recommended to
         switch off the mode (command 'c') and change display units to
         sectors (command 'u').

Command (m for help): n
Command action
   e   extended
   p   primary partition (1-4)
p
Partition number (1-4): 1
First cylinder (1-261, default 1):
Using default value 1
Last cylinder, +cylinders or +size{K,M,G} (1-261, default 261):
Using default value 261

Command (m for help): w
The partition table has been altered!

Calling ioctl() to re-read partition table.
Syncing disks.

 

[root@asmlnx2 ~]# partprobe  /dev/xvdv

 

[root@asmlnx2 ~]# partprobe  /dev/xvdv1

 

[root@asmlnx2 ~]# ls -l  /dev/xvdv
brw-rw---- 1 root disk 202, 5376 Feb 11 21:38 /dev/xvdv

 

[root@asmlnx2 ~]# ls -l  /dev/xvdv1
brw-rw---- 1 root disk 202, 5377 Feb 11 21:38 /dev/xvdv1

[root@asmlnx2 ~]# vi /etc/udev/rules.d/99-oracle-asmdevices.rules
KERNEL=="xvdv1", NAME="asmdisk1_udev_p1", OWNER="grid", GROUP="asmadmin", MODE="0660"

[root@asmlnx2 ~]# udevadm control --reload-rules

[root@asmlnx2 ~]# start_udev
Starting udev:                                             [  OK  ]

[root@asmlnx2 ~]# ls -ltr /dev/asm*
brw-rw---- 1 grid asmadmin 202, 5377 Feb 11 21:47 /dev/asmdisk1_udev_p1

[root@asmlnx2 ~]# su - grid
[grid@asmlnx2 ~]$ . oraenv
ORACLE_SID = [grid] ? +ASM
The Oracle base has been set to /u01/app/grid
[grid@asmlnx2 ~]$ sqlplus "/as sysasm"

SQL*Plus: Release 11.2.0.3.0 Production on Mon Feb 11 21:56:31 2013

Copyright (c) 1982, 2011, Oracle.  All rights reserved.


Connected to:
Oracle Database 11g Enterprise Edition Release 11.2.0.3.0 - 64bit Production
With the Automatic Storage Management option


SQL> show parameter asm_diskstring

NAME                                 TYPE        VALUE
------------------------------------ ----------- ------------------------------
asm_diskstring                       string


SQL> alter system set asm_diskstring = '/dev/asmdisk1_udev_p1' scope=both;

System altered.


SQL> show parameter  asm_diskstring

NAME                                 TYPE        VALUE
------------------------------------ ----------- ------------------------------
asm_diskstring                       string       /dev/asmdisk1_udev_p1



SQL> select path from v$asm_disk where path like '%udev%';

PATH
--------------------------------------------------------------------------------
/dev/asmdisk1_udev_p1


SQL> create diskgroup UDEVDG external redundancy disk '/dev/asmdisk1_udev_p1'  ;

Diskgroup created.