On Dec 3, 2010, at 7:48 PM, Gordon Messmer <yinyang at eburg.com> wrote: > On 12/03/2010 03:48 PM, Ross Walker wrote: >> >> If the protocol is latency sensitive then jumbo frames are BAD as it >> adds more latency because frames take longer to fill, longer to >> transmit and thus other conversations have to wait longer (poor >> pipelining/interlacing). >> >> CIFS/NFS aren't really latency sensitive protocols though. If a >> protocol has a big TCP window then it will not tend to be latency >> sensitive. > > I measure better throughput on NFS with jumbo frames than without. > Measurement trumps assertions. :) All I was trying to get across is that jumbo frames aren't to be used in latency sensitive applications as it adds latency. As your findings show NFS is not a latency sensitive application and thus why you see better throughput with jumbo frames. That is also why NFS/CIFS can be used over a WAN while a latency sensitive protocol such as iSCSI is almost useless over the WAN. -Ross