Todd And Margo Chester writes:
> Can anyone tell me what this means?
> 
>     just disable jumbo frames on centos host interface
>     ifcfg and ethernet switch.

MTU=9000 is a "jumbo frame".  Lots of data stuck onto the same sized IP
header means more data going through for the same administrative
overhead.

I think most times things default to 1500, so you have to go out of your
way to set this up (I do in order to get 8k sized nfs packets through on
our local net).  Including the switches and routers: if I send a 9000
byte packet through and it hits a switch along the way which is set for
1500, it will chop it up into a lot of smaller packets before passing it
along: destroying any performance advantage I'd hoped to get.

Anyway: set the MTU to something smaller (more normal?) and "jumbo
frames" are disabled, at least from a naive user's perspective.  There
are probably more subtle kernel network stack issues I'm not aware of.

-- 
 	    Alec Habig, University of Minnesota Duluth Physics Dept.
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		       http://neutrino.d.umn.edu/~habig/