On 2013/10/01 23:02, Abel Abraham Camarillo Ojeda wrote: > > On Fri, 23 Aug 2013 18:39:29 -0500, Abel Abraham Camarillo Ojeda > > <acam...@verlet.org> wrote: > >> Not yet, will test. > >> > >> On Thu, Aug 22, 2013 at 7:05 AM, Stuart Henderson <s...@spacehopper.org> > >> wrote: > >>> On 2013-08-22, Abel Abraham Camarillo Ojeda <acam...@verlet.org> wrote: > >>>> Is there a way to duplicate the throughput of a single > >>>> TCP connection using two servers having two gigabit NICs? > >>>> > >>>> I have tried using LACP but I cannot get more than > >>>> 900MB of throughput... > >>> > >>> LACP uses a hash over IP addresses/vlan tags/flowlabel to avoid > > problems > >>> with out-of-order packet delivery. (Similar for equal-cost multipath). > >>> Have you tried a roundrobin trunk yet? > > Stuart: > > Trying between two obsd hosts only (no switch) I was able to get > more than 1000Mb speed testing with tcpbench but only using great > values for -n option (-n >16)... > > Is there a way to aggregate (reliably) a single TCP connection using an > LACP capable switch between two OpenBSD hosts? > > I'm using this: > > http://www.amazon.com/Cisco-SG200-26P-Ethernet-Mini-GBIC-SLM2024PT/dp/B004GHMU5Q > > Thanks
I'm not aware of any LACP implementation on switches which does per-packet balancing. Even if you hack your kernel so that LACP trunks use round-robin to determine the output port (rather than hashes of headers), that is only on the link *to* the switch. Once the switch has received a packet, it will use its own algorithm to choose the output port. Typically the switch will use a hash of ethernet headers i.e. src/dest MAC and vlan tags - expensive switches will allow more options but usually even then it's no more than src/dest IP and port numbers. Even if you can find some way around this, some packets will arrive out-of-order which will cause individual TCP flows to slow down, so even in that case it's pretty unlikely to really help actual performance. It sounds like what you really need here is 10GE kit. Motherboard/NIC ports aren't too bad now, but if you want more than 2-4 10GE ports on a switch (to mention some of the "cheaper" options: xgs1910-24, gsm7228s, sg500x-24) then the switches start to get rather expensive.
