Coda File System

Re: difference between replicated and nonreplicated shares

From: Stephen J. Turnbull <>
Date: Tue, 13 Jul 2004 09:49:29 +0900
>>>>> "Andrea" == Andrea Prunic <> writes:

    Andrea> Now, is AFS better because it can do what I want to, or
    Andrea> not?

AFS also requires centralized servers.

    Andrea> Yes, I've put a root server on my machine, and another
    Andrea> replica server on coleagues machine.

There's no real point to this with Coda, unless you just want to make
sure that burdens are equally high on everybody.  (A _small_ number of
replicas is justified in the name of security, of course.  What I mean
is that there's no need for all people wishing to offer files for
sharing to run servers.)  The way Coda works is that a file in use is
_always_ replicated (in the day-to-day sense): there's a copy on the
server, and a copy on the client.

However, if you don't use the client's copy, and take no special
action, it will disappear.  So Coda conserves space on the client
workstations, it does not share it.

    Andrea> some p2p solutions, which on the other hand, is not
    Andrea> exactly what we had in mind...

Of course P2P is _exactly_ what you describe (files residing on
individual workstations being offered for share, with a central
directory service), with the additional requirement that the directory
service be transparently presented as a Unix filesystem.

I believe that on Linux, at least, it is possible to reexport NFS
filesystems.  That sounds to me like what you want.  You have a
central virtual server which doesn't offer any files itself, just
reexports other NFS filesystems, which are offered by the individual

But really, for music files can't you afford a couple of extra 100GB
hard drives to set up a Coda server?  Coda seems ideal for the
application you sketch.

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Received on 2004-07-12 20:51:20