Using NFS with Scyld (-7 ver.)

[Donald Becker]

On Mon, 5 Nov 2001, Daniel Kidger wrote:
> > As far as I know, you cannot get a linux box to mount an NFS filesystem,
> > then reexport it over NFS to another machine.  So, as far as I know,
> > what you're asking is impossible.
> 
> I have never seen re-exporting a directory working.

It does work: I wrote the original user-level NFS server (unfsd) used by
Linux, and re-exporting was one of the primary advantages over the Sun
implementation.  Having a per-client user ID map was another.

> What you can do is routing with ipchains so all nodes on a cluster's private
> ethernet can mount a filesystem on an external system.  

That's a better approach for most clusters, however you can get better
caching when using re-export from the master.  the NFS consistency
problem on writes affects either approach.  We recommend only using NFS
for small read-only configuration files in /home.


Donald Becker				becker at scyld.com
Scyld Computing Corporation		http://www.scyld.com
410 Severn Ave. Suite 210		Second Generation Beowulf Clusters
Annapolis MD 21403			410-990-9993