[vox-tech] mmap()

[Bill Broadley]

On 10/22/2013 03:45 PM, Norm Matloff wrote:
> Anyone here know much about mmap()?  I have following problem:
>
> Machines A and B, running Fedora, share files through NFS.  I use mmap()
> to create a file-backed array on A and B, shared via the common file
> system.  I want changes to the array at A to propagate to B and vice
> versa.
>
> I can't get this to work consistently, even using msync() (synchronous
> or asynchronous).
>
> This is for general use software, so using a "better" shared file system
> than NFS is not really an option.

Which mount options for NFS?  Which version of NFS?  This kind of thing 
needs byte range locking, which requires nfs v4.  Sync or Async?

To test byte range locking there's a test suite:
http://nfsv4.bullopensource.org/tools/tests/locktest.php

If that doesn't work I don't think sharing mmaped files via nfs is going 
to work.