Re: Poor Performance for ethernet bonding

[Thomas Davis <tadavis@lbl.gov>]

Ben Greear wrote:
> 
> Couldn't the bonding code be made to distribute pkts to one interface or
> another based on a hash of the sending IP port or something?  Seems like that
> would fix the reordering problem for IP packets....  It wouldn't help for
> a single stream, but I'm guessing the real world problem involves many streams,
> which on average should hash such that the load is balanced...
> 

Cisco etherchannel does this, by XOR'ing the dest address with the
source address, AND'ing with # of interfaces (limiting you to a power of
2), and then using the number to determine what channel to use.

Now, you end up in a 4 way Etherchannel, all the traffic going down one
channel, and the none going down the other three.  Does that sound like
a balanced solution?

Most bonding problems are either the card driver is busted, the card is
busted (el-cheapo NE2000 PCI clones are really bad..) or the switch
can't handle it.  Most cheap, dumb switches break big time when using
Bonding with them.


-- 
------------------------+--------------------------------------------------
Thomas Davis		| ASG Cluster guy
tadavis@lbl.gov		| 
(510) 486-4524		| "80 nodes and chugging Captain!"