Using a Permissions File with Oracle Enterprise Linux 4.0

When you restart a Red Hat Enterprise Linux 4.0 system, ownership and permissions on block devices revert by default to the root user. If you are using block devices with this operating system for ASM disk group files, then you need to override this default.

To create a permissions file if you are using Red Hat Enterprise Linux 4.0:

Log in to the operating system as the root user.
Change to the /etc/udev/permissions.d directory.
Use a text editor to create a file named 49-oracle.permissions to ensure correct ownership of the block devices when the operating system is restarted.

The following is an example of the contents of the /etc/udev/permissions.d/49-oracle.permissions file:
```
# ASM
sda:oracle:dba:0660
sdb:oracle:dba:0660
sdc:oracle:dba:0660
sdd:oracle:dba:0660
sde:oracle:dba:0660
```
Save the file.
(Optional) After creating the oracle.permissions file, the permissions on the shared devices are set automatically the next time the system is restarted. To set permissions to take effect immediately, without restarting the system, use the chown and chmod commands:
```
chown oracle:dba  /dev/sda
chmod 660 /dev/sda
chown oracle:dba  /dev/sdb
chown 660 /dev/sdb
chown oracle:dba /dev/sdc
chown 660 /dev/sdc
chown oracle:dba /dev/sdd
chown 660 /dev/sdd
chown oracle:dba /dev/sde
chown 660 /dev/sde
```
Repeat these steps on each node in the cluster.