Running inn under 64x.

["Miquel van Smoorenburg"]

In article <45C0FEFD.2050409 at gmx.at>,
Alexander Bartolich  <alexander.bartolich at gmx.at> wrote:
>Miquel van Smoorenburg wrote:
> > [...]
> > BTW, using /dev/sdXX directly isn't all that ideal ..
> > try rawfs
> > from ftp://ftp.xs4all.nl/pub/people/miquels/kernel/v2.6/
>
>http://groups.google.com/group/news.software.nntp/msg/db66ecb5946cf29f
># Message-ID: <alaihu$29u$1 at ncc1701.cistron.net>
># Date: Fri, 6 Sep 2002 15:45:02 +0000 (UTC)
># From: "Miquel van Smoorenburg" [...]
># [...]
># Blockdevices in 2.2 kernels don't have mmap() support, so you can't
># use them directly for CNFS. So I wrote a 'rawfs' that simply maps
># partitions to fixed-size files.
># [...]
># With linux-2.4 kernels this isn't needed anymore since you can
># just use /dev/sdb1 directly.
>
>I am using 21 logical volumes of 2 GB each with "articlemmap"
>and "use-mmap" enabled, on Debian Sarge with a kernel from Sid.
>No problems so far.

I don't know .. rawfs feels faster to me. Probably because
I/O to /dev/sdxx doesn't use the pagecache, but the old buffercache.
Also I remember Andrew Morton once saying that mmap()ing a
blockdevice works, but it isn't in any way optimized.
I went back to using rawfs even on 2.4 and 2.6. But then again
I was maxing out a 1 gbit/s link on a box with a Pentium 2.4 Ghz,
1 GB of RAM and plain SATA disks, and for that I needed every
bit of performance I could get :)

A lot of things have changed 2.4 -> 2.6, it could be that
rawfs in current 2.6 is not really needed anymore.

Mike.
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