[INS-30508] Invalid ASM Disk: RHEL6 adding asm disk

Invalid ASM Disk: RHEL6 adding asm disk
One may face following error during adding ASM disk on RHEL6:
[INS-30508] Invalid ASM Disk: RHEL6 adding asm disk
Oracle has discontinued support for asmkernel expect for OEL6, if you do not want to go for OEL6 and still adding disk, permission for block device will get change everytime

brw-rw----. 1 oracle dba  8, 80 Jul 19 01:13 sdf
[root@ora2 dev]# ls -l sd*
brw-rw----. 1 root disk 8,  0 Jul 19 01:12 sda
brw-rw----. 1 root disk 8,  1 Jul 19 01:12 sda1
brw-rw----. 1 root disk 8,  2 Jul 19 01:12 sda2
brw-rw----. 1 root disk 8,  3 Jul 19 01:12 sda3
brw-rw----. 1 root disk 8, 16 Jul 19 01:12 sdb
brw-rw----. 1 root disk 8, 17 Jul 19 01:12 sdb1
brw-rw----. 1 root disk 8, 18 Jul 19 01:13 sdb2
brw-rw----. 1 root disk 8, 19 Jul 19 01:13 sdb3
brw-rw----. 1 root disk 8, 32 Jul 19 01:42 sdc
brw-rw----. 1 root disk 8, 48 Jul 19 01:42 sdd
brw-rw----. 1 root disk 8, 64 Jul 19 01:42 sde
brw-rw----. 1 root disk 8, 80 Jul 19 01:42 sdf

Workaround for this is to create udev rule for asm disks.

Follow below steps for this:

[root@ora2 ~]# cd /etc/udev/rules.dvi 
[root@ora2 rules.d]# vi 99-oracle-asmdevices.rules  

and add entry:

KERNEL=="sdc", SUBSYSTEM=="block", ENV{DEVTYPE}=="disk",  OWNER="oracle", GROUP="dba", MODE="0660"
KERNEL=="sdd", SUBSYSTEM=="block", ENV{DEVTYPE}=="disk",  OWNER="oracle", GROUP="dba", MODE="0660"
KERNEL=="sde", SUBSYSTEM=="block", ENV{DEVTYPE}=="disk",  OWNER="oracle", GROUP="dba", MODE="0660"
KERNEL=="sdf", SUBSYSTEM=="block", ENV{DEVTYPE}=="disk",  OWNER="oracle", GROUP="dba", MODE="0660"

Save & exit.

[root@ora2 dev]# start_udev
Starting udev:                                             [  OK  ]
[root@ora2 dev]# ls -l sd*
brw-rw----. 1 oracle dba  8, 32 Jul 19 01:58 sdc
brw-rw----. 1 oracle dba  8, 48 Jul 19 01:58 sdd
brw-rw----. 1 oracle dba  8, 64 Jul 19 01:58 sde
brw-rw----. 1 oracle dba  8, 80 Jul 19 01:58 sdf