Re: [Gnu-arch-users] a global-scale txnal distributed filesystem

[Jan Hudec]

On Wed, Jun 16, 2004 at 09:52:17 -0700, Tom Lord wrote:
> 
>     > From: Andrew Suffield <address@hidden>
> 
>     > > There's a gazillion little details and elaborations on the general
>     > > idea sketched above but I haven't been able to think of any that
>     > > aren't trivial.
> 
>     > Authentication and authorisation. With NFS, the answer is basically
>     > "don't"; it not only fails to even attempt to solve the problem, but
>     > makes it several times harder. You could only really use this in
>     > trusted environments.
> 
>     > NFSv4 would be viable for this, but NFSv4 itself is not yet viable,
>     > and has little in common with earlier NFS versions - it's a
>     > not-completely-stupid network filesystem, which means it's nowhere
>     > near as simple.
> 
> The only reason to pick NFS is for convenience of implementation.  I
> don't know of any other portable way to write a user-space filesystem.

There is a bit less portable, but by far easier method, using the coda
interface. Coda has the client (cache-manager) in userland and it's
interface to kernel is rather trivial. The requests go along a device
and the data go in temporary files. Glue between this interface and
midnight vfs library has about 500 lines (see uservfs.sf.net). An old
NFS implementation had about four times as much.

> Any other way to do a created-on-demand filesystem with the ability
> to remap paths name would work as well.

FUSE library supports both the coda local interface and NFS.
The coda interface seems to be available on many unices, but the project
pages fail to provide easy-to-spot list of supported systems.

-------------------------------------------------------------------------------
                                                 Jan 'Bulb' Hudec 
<address@hidden>

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