[mythtv-users] Re: Samba 3 better than NFS 3 for recording over Ethernet

Greg Oliver goliver at cistera.com
Thu Dec 29 00:32:10 EST 2005


Jumbo frames are your friend

On Wed, 2005-12-28 at 21:29 -0800, Jonathan Tidmore wrote:
> On 12/28/05, Mike Frisch <mfrisch at isurfer.ca> wrote:
>         
>         The "tcp" option may not be necessary but I haven't taken the
>         time to
>         benchmark between TCP and UDP.
> 
> 
> For gigabit ethernet, the nfs people recommend TCP.
> 
> From the man page for nfs (5): 
> 
> WARNINGS
>        Using NFS over UDP on high-speed links such as Gigabit can
> cause silent data corruption.
> 
>        The  problem  can  be  triggered at high loads, and is caused
> by problems in IP fragment reassembly. NFS 
>        read and writes typically transmit UDP packets of 4 Kilobytes
> or more, which have to be broken  up  into
>        several  fragments  in  order  to  be sent over the Ethernet
> link, which limits packets to 1500 bytes by 
>        default. This process happens at the IP network layer and is
> called fragmentation.
> 
> They go into greater detail about this issue.  For info use 'man 5
> nfs'
> 
> 
> -J
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