[Radiance-general] NFS and rpiece

[Francesco Anselmo]

Hi Jack,

Thanks for your extremely useful input on this topic.

> I have struggled with NFS based file locking (on Linux) on and off for
> quite some time. Most of our work usually uses smp nodes so this is
> normally not an issue. 
> But I have been looking back into this more recently for some cluster
> based rendering. I would seriously suggest taking a look at:
>         http://nfs.sourceforge.net/
> Which has a fairly extensive set of information on NFS.

Thanks for pointing me to this URL, I should have checked it before.
Effectively it is the single most useful resource about NFS on linux :)
so much better than the man pages.

> For locking to work correctly I am pretty sure that you need to
> specify the (sync) option on the server and/or the client side.
> However NFSv3 is supposed to do sync by default as apposed to v2 which
> did aysnc. The latter is faster however leads to a wide variety of
> issues. It is quite likely that you also need to specify the (noac)
> option, which means that the client is not caching file status
> information instead it always goes to the server to check the file
> status. Both of these options together make things slow... To improve
> performance I believe that you can do a couple of things: 1) increase
> number of nfsd processes available to handle requests and 2) specify
> larger rsize and wsize (assuming a fast network transport).

I will ask to change the configuration next Monday, and hopefully
things should improve.

> Please note that I have been trying to read up on this as well as
> other shared filesystems, I have not had a chance to test a lot of
> this out. I would be interested to hear what you learn.

Yes, I'll keep you updated on my trials&errors.

I have been using OpenMosix with oMFS so far, and it has been working
properly, especially after the DFSA has been introduced.
(for more info about oMFS and DFSA there is a short section in
http://howto.x-tend.be/openMosixWiki/index.php/FAQ)

I understand that the OpenMosix development is moving towards using
GFS (Global File System) now:
http://www.redhat.com/whitepapers/rha/gfs/GFS_INS0032US.pdf

Thanks again, and have a nice week-end.

Francesco