DEPRECATION OF RAW DEVICES IN LINUX 2.6 KERNELS
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Starting with the 2.6 Linux kernel, raw devices are being phased
out in favor of O_DIRECT access directly to the block devices.

With Oracle RDBMS 10.2.0.2 and higher, block devices can be accessed via
any of the following methods, and utilized by RDBMS:

- Directly to the block device
- Via ASMLib mapped devices
- OCFS2 devices (Note: OCFS2 is still Pending Certification)
- LVM2 mapped devices if single-instance

SCRIPT TO MIGRATE RAW TO BLOCK DEVICES
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Moving from RAW devices to O_DIRECT opened block devices is simple.
Just link the raw device files which used to exist to their corresponding
block device. For example, instead of running "raw /dev/raw/raw5 /dev/sdc1"
the should do "ln -s /dev/sdc1 /dev/raw/raw5".

This can be automated from the /etc/sysconfig/rawdevices file via the
following script:

#!/usr/bin/env perl
/^s*#/ and next;

/^(S+)s+(d+)s+(d+)/ and do {
my ($rawname, $major, $minor) = ($1, $2, $3);
$syspath = qx!find /sys/block -name dev | xargs grep -l "^$major:$minor$" !;
@pathelem = split '/', $syspath;
print "ln -s /dev/$pathelem[$#pathelem-1] $rawname";
} or
/^(S+)s+(S+)/ and print "ln -s $2 $1";

Save script as rawfinder.pl and run it with:

$ perl rawfinder.pl /etc/sysconfig/rawdevices

This will print out the list of symlinks to create.

REFERENCES
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Notes in /etc/sysconfig/rawdevices as follows, from a RHEL4 system:

# This file and interface are deprecated.
# Applications needing raw device access should open regular
# block devices with O_DIRECT.
# raw device bindings
# format: <rawdev> <major> <minor>
# <rawdev> <blockdev>
# example: /dev/raw/raw1 /dev/sda1
# /dev/raw/raw2 8 5