On 6/26/11, Gordon Messmer yinyang@eburg.com wrote:
I don't know anything specifically about those cards, but you'll see that behavior on any card unless all of the hosts on a broadcast domain are using the same MTU. You need to set all of the devices on a LAN segment, including the router, to the same MTU.
Thanks for this note, but it didn't seem to be necessary in my case.
I just finished updating the drivers and running some test, the results were this.
In all cases, default 1500 MTU to 1500MTU = OK for both default and Elrepo drivers.
NFS Host -> NFS Client Default Drivers for both 1500 MTU -> 3000 MTU = fail 3000 MTU -> 3000 MTU = fail
Default Driver -> ElRepo driver 1500 MTU -> 3000 MTU = OK 3000 MTU -> x MTU = fail
ElRepo -> ElRepo driver Both OK
So the MTU problem appears to be firmly pinpointed to the default RTL drivers and both receiving/transmitting NICs must be using the ElRepo drivers to work properly at higher MTU.
Ironically, even at 1500MTU, I was able to hit the full 100+ MB/s speed available on a single Gigabit link so it seems my experiment was a bit futile.