flock and NFS

[Ben Scott]

On Fri, Apr 10, 2009 at 1:39 PM, Jeff Macdonald <macfisherman at gmail.com> wrote:
> I've always been wary of using flock on NFS. Am I being superstitious?

  It's been awhile, but as I recall, locking was generally working
okay within a given NFS implementation.  It was interoperability where
things really got hairy.  So, e.g., a Sun NFS server with a Linux NFS
client was problematic.  Linux everywhere was okay.

  You need to be running a lock daemon on ... uh, either the client,
the server, or maybe both.  Whenever I use NFS on Linux, I always just
start every service I can find that has anything to do with NFS or
RPC.  That way I know I started the ones I need.  :)

> How can I determine if the proper NFS components are in
> place in order for the programs to function correctly?

  I would find, or if needed write, a trivial test program for the
flock() functions, and run a few instances on different nodes.  That
way you'll have verified assurance that it's working.

-- Ben