[SGVLUG] Distributed filesystems

[Chris Smith]

On 6/23/05, Terry Hancock <hancock at anansispaceworks.com> wrote:
> On Wednesday 22 June 2005 05:29 pm, John Riehl wrote:
> > what is your network like?   switch or hub?  wires or wireless? what is
> > your server like?
> 
> It's a mess and it's antiquated, but I am not motivated to fix that if this
> is the only use case (and it is).  Copying files from one system to another
> is not inordinately slow, but anything that requires fast disk performance
> obviously suffers from use over NFS.

Interestingly, at work we use NFS for all of our high performance stuff. ;-)

> No doubt this has to do with using
> an ancient 10 mbit hub and driver problems on at least one ethernet card,
> but somehow my antiquated, "bottlenecked", "poorly configured" network
> manages to wheeze through most tasks I need it for.

If NFS is slower than other stuff then those aren't the problem areas.
It's probably something quite simple. If the network really is your
problem, then NFS isn't really adding much overhead on top of this (on
a bad day maybe 5%), so switching to something else isn't going to
change your experience much.
 
> I would hope it is clear that using *ANY* system which accesses data
> on a remote system's hard drive is going to be slow compared to getting
> it from a local drive.

So you don't actually want a distributed filesystem....
 
> > certainly rsyncing your files locally and running that will avoid the
> > problem. I dont think your problem is inherently NFS.
> 
> That's probably the best solution, I guess. I had been thinking that it
> might be easier to set up a solution at the filesystem level.  But it sounds
> like not.   Rsync and a cron job may be the best thing, I suppose.

You could use AFS, but you'll get a horrid experience whenever you get
a cache miss, and I suspect you'll be quite angry. rsync is probably
the simplest way to go here, but in general you are describing is
*replication system* not a filesystem. You could use a version control
system, but that really stinks for binaries. I mentioned "union"
before, what I meant was "unison":

http://www.cis.upenn.edu/~bcpierce/unison/

Maybe that's more what you're looking for.

-- 
Chris