[mythtv-users] mythtv + nfs = bad?

[Nasa]

----- "Dale Pontius" <DEPontius at edgehp.net> wrote:

> Brian Wood wrote:
> > On Thursday 07 May 2009 07:43:38 James Oltman wrote:
> >> On Wed, May 6, 2009 at 6:55 PM, Brian Wood <beww at beww.org> wrote:
> >>> What version of NFS?
> >>>
> >>> I think NFS v.2 (client side) has a 2GB file size limit, which
> means it
> >>> can only look at the first 2GB of a file that's larger than 2GB.
> >>>
> >>> Version 3 supports larger files, but obviously it depends on the
> >>> filesystem on
> >>> the server side, if it were FAT, for example, a 4.7GB file would
> be a
> >>> problem.
> >>>
> >>> There is also a limit on the size of a transfer "on the wire",
> which
> >>> depends
> >>> on whether TCP or UDP is used, and the particular implementation.
> >>>
> >>> Large files and NFS can be problematical, make sure you understand
> any
> >>> limits
> >>> of your server and client NFS versions, as well as the filesystem
> in use.
> >>>
> >>> Google "nfs file size limits" for more information.
> >> Brian,
> >>
> >> Thanks for the response.  What was strange about my setup was that
> it was
> >> working just fine for a long time.  Then all of the sudden, one
> day, it
> >> stopped working.  I don't know if it happened during a kernel
> update or
> >> what.  I know I'm running NFSv2.  I don't know how to update myself
> to v3
> >> or above.
> > 
> > 
> > The precise upgrade method would depend on your distribution, any of
> the most 
> > recent distros should have support for v3. I'd consult the relevant
> support 
> > fori.
> > 
> > Even if (for example) an upgrade to your server side machine enabled
> nfs v3, 
> > the systems should negotiate the highest commonly supported version,
> so if 
> > your client can only do v2, that's what the server should do as
> well.
> > 
> > There have also been some changes in the default settings for
> sync/async, and 
> > some others I think.
> > 
> > But using "mixed" systems might cause problems.
> > 
> > Another user here noted an improvement in performance by using samba
> mounts 
> > instead of NFS, certainly sounds like it's worth a try. I'm going to
> look 
> > into that, and try to get some hard numbers.
> > 
> > I'm certainly no expert on NFS, I use it for non-Myth applications
> and it has 
> > always "just worked", but I don't put much demand on it. 
> > 
> I'm running nfs4 and still have the problems.  It's supposed to be 
> ironed out by the time client and server get to 2.6.29 or beyond.
> 
This discussion got me to do some googling....  I came across some discussion, such as here:

http://www.ncsa.uiuc.edu/UserInfo/Resources/Hardware/IBMp690/IBM/usr/share/man/info/en_US/a_doc_lib/aixbman/prftungd/2365ca3.htm

which eventually led me to see this...

http://kamilkisiel.blogspot.com/2007/11/understanding-linux-nfsd-statistics.html

Those combined with some more research led me to believe I wasn't running enough nfsd daemons.  The default of 8 just isn't good enough -- does that account for the
problem I was seeing, I guess time will tell.  But it's at least a start.

Nasa