Yet another filesystem - sffs

Yet another filesystem - sffs

[Bernard Hatt]

I had an idea for a filesystem as an alternative to using a raw disk
partition for storing a single (large) data file (eg. a DVD image or a
database data file), adding the convenience of a file length, permissions
and a uid/gid.

As I now have some functional code (a 'compile outside the kernel'
module, only tested against i386/2.6.9) I thought I'd share the sffs
(single file file-system) code for comments/testing.

Performance for a single file is between 0 and 40% faster than ext2,
(though sffs is not a general purpose filesystem).

Some more details/benchmarks:
         http://www.arkady.demon.co.uk/sffs
the code can be downloaded from:
         http://www.arkady.demon.co.uk/sffs/sffs-latest.tar.gz (13.5k)

Regards,

Bernard

Re: Yet another filesystem - sffs

[Miquel van Smoorenburg]

In article <41AC2DBE.1080501@ntlworld.com>,
Bernard Hatt  <bernard.hatt@ntlworld.com> wrote:
>I had an idea for a filesystem as an alternative to using a raw disk
>partition for storing a single (large) data file (eg. a DVD image or a
>database data file), adding the convenience of a file length, permissions
>and a uid/gid.
>
>As I now have some functional code (a 'compile outside the kernel'
>module, only tested against i386/2.6.9) I thought I'd share the sffs
>(single file file-system) code for comments/testing.

I've been using such a filesystem for years, since Linux 2.0 ..
It's at ftp://ftp.cistron.nl/pub/people/miquels/kernel/v2.[0246]/rawfs-*

I use it with the CNFS (Cyclic News File System) storage option
of INN for high-performance usenet news transit systems.

Mike.

Re: Yet another filesystem - sffs

[Bernard Hatt]

Miquel van Smoorenburg wrote:
> I've been using such a filesystem for years, since Linux 2.0 ..
> It's at ftp://ftp.cistron.nl/pub/people/miquels/kernel/v2.[0246]/rawfs-*

> Mike.

Yes, it depends how much functionality you *need*, sffs implements
more file operations so that you can do things like:
	mkisofs -o /mnt/test/blah.iso  [...]
and	cdrecord -v -data /mnt/test/blah.iso (without needing isosize).

But what is odd, having run my benchmarks on rawfs, that sffs
is faster by between (0.5% and 4.6%) where I was expecting
almost identical results (but then, benchmarks aren't everything).

Regards,

Bernard

Re: Yet another filesystem - sffs

[Pavel Machek]

Hi!

> I had an idea for a filesystem as an alternative to using a raw disk
> partition for storing a single (large) data file (eg. a DVD image or a
> database data file), adding the convenience of a file length, 
> permissions
> and a uid/gid.

Long time ago, Martin Mares did something very similar, IIRC it was called
smugfs.
				Pavel
-- 
64 bytes from 195.113.31.123: icmp_seq=28 ttl=51 time=448769.1 ms         

Re: Yet another filesystem - sffs

[Martin Mares]

Hi!

> Long time ago, Martin Mares did something very similar, IIRC it was called
> smugfs.

Actually, it was a bit smarter (but just a small bit :) ) -- it allowed
multiple files and allocated space by dividing the whole partition to
256 blocks and remembering a single-sector FAT-like structure. However,
no subdirectories were supported.

The code is probably of historical interest only, but you can find it
at ftp://atrey.karlin.mff.cuni.cz/pub/local/mj/linux/smugfs-0.0-2.0.32.tar.gz.
Once it worked, but I don't believe it's SMP safe.

				Have a nice fortnight
-- 
Martin `MJ' Mares   <mj@ucw.cz>   http://atrey.karlin.mff.cuni.cz/~mj/
Faculty of Math and Physics, Charles University, Prague, Czech Rep., Earth
"First they ignore you. Then they laugh at you. Then they fight you. Then you win." -- Gandhi