Hi Dude!, that makes sense for me. And I have another related question about how udev control the disk ownership differently in OEL5 and OEL6? Thanks.
In OEL 5, when I change the ownership of a disk say /dev/sde from root:disk to oracle:dba. The udev would not reset the disk ownership utill a reboot.
# udevinfo -V
udevinfo, version 095
# uname -r
In OEL 6, when I do the same ownership change of the /dev/sde, the ownership would reset to root:disk quickly or after some operations like asmca
# udevd --v
# uname -r
Again that's because as of the 2.6 kernel, the /dev tree is rebuild after every system restart, hence resetting your device ownerships back to root. Also keep in mind, that when you use more than one physical device, the device order, such as sda or sdb, can change, for instance if you have a USB drive attached during a system startup.
You can address the issue in OL5 and OL6 by configuring udev rules to accomplish device name persistence and also set device ownerships. Or install and configure Oracle ASMLib, which also takes care of it.