[mythtv-users] mythtv + nfs = bad?

Dale Pontius DEPontius at edgehp.net
Fri May 8 00:24:33 UTC 2009

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.


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