Re: serious networking (em) performance (ggate and NFS) problem

Am Donnerstag, 18. November 2004 00:17 schrieb Sean McNeil:
> On Wed, 2004-11-17 at 23:57 +0100, Emanuel Strobl wrote:
> > Dear best guys,
> >
> > I really love 5.3 in many ways but here're some unbelievable transfer
> > rates, after I went out and bought a pair of Intel GigaBit Ethernet Cards
> > to solve my performance problem (*laugh*):
> >
> > (In short, see *** below)
[...]
> > Conclusion:
> >
> > ***
> >
> > - It seems that GEOM_GATE is less efficient with GigaBit (em) than NFS
> > via TCP is.
> >
> > - em seems to have problems with MTU greater than 1500
> >
> > - UDP seems to have performance disadvantages over TCP regarding NFS
> > which should be vice versa AFAIK
> >
> > - polling and em (GbE) with HZ=256 is definitly no good idea, even
> > 10Base-2 can compete
> >
> > - NFS over TCP with MTU of 16114 gives the maximum transferrate for large
> > files over GigaBit Ethernet with a value of 17MB/s, a quarter of what I'd
> > expect with my test equipment.
> >
> > - overall network performance (regarding large file transfers) is
> > horrible
> >
> > Please, if anybody has the knowledge to dig into these problems, let me
> > know if I can do any tests to help getting ggate and NFS useful in fast
> > 5.3-stable environments.
>
> I am very interested in this as I have similar issues with the re
> driver.  It it horrible when operating at gigE vs. 100BT.  Have you
> tried plugging the machines into a 100BT instead?

No, because I observed similar bad performance with my fileserver which is 
almost the same HW and it's em (Intel GbE) is connected to the local 
100baseTX segment.
I explicitly avoided to go via any switch/hub to eliminate further problems.
I wonder if anybody has ever been able to transfer more than 17MB/s via IP 
anyway?
I need this performance for mirroring via ggate, so I'm thinking about fwe (IP 
over Firewire).
Perhaps somebody has tried this already? If fwe gives reasonable transferrates 
I guess the perfomance problem won't be found in ethernet but in IP.

Thanks,

-Harry

>
> Cheers,
> Sean