On Thu, 2006-03-23 at 14:54 +0530, Yogesh Pahilwan wrote:

Hi All,

I want to do raw I/O on MD RAID and LVM for fedora core 4(kernel 2.6.15.6).

After doing googling I came to know that "raw" command does the raw
operation by linking 
MD device and LVM volume to the raw device as 

# raw /dev/raw/raw1 /dev/md0.

But when I search on this I came to know that there is no raw (/dev/rawctl)
device support available with 2.6 kernel.
I have also tried recompile the kernel sources with raw device support it is
not getting compiled as it is obsolete in 2.6. 
If I want to include raw device support in my kernel what should I will have
to do, so that I 

the preferred interface is doing O_DIRECT io on the device node itself,
rather than going via a (slower) indirection layer such as "raw". ("raw"
is just a wrapper on top of O_DIRECT basically in 2.6 kernels so slower)