Charlie Meyer wrote:
I ive set up a working linux router with load balancing as per the lartc
guide. Everything is working properly, except for the load balancing
does not seem to be equally balance the load. The first line gets about
60% of the incoming load, the 2^nd line gets about 40%, and the 3^rd
line hardly gets any of it at all. The outgoing load is evenly balanced
among all three lines.
I did not set any weights when I set up the route, so this is confusing
to me. BTW, I have been using ntop as well as ibmonitor to view the load
over each line.
when I have tried setting weights, such as 1 for the first line, 2 for
the second line, and 4 for the second line, it still doesn’t balance
correctly.
I am using fedora core 6 with all the latest packages and kernel as per yum.
any ideas here would be greatly appreciated
Keep in mind that you do not have any control of the traffic that is
inbound to you. The only thing that you can control is the traffic that
you send.
So, what is probably happening is that your system is load balancing the
out bound traffic, which is being replied to by the server. Consider
you have 3 connections, one out bound request each. Unless you are
dealing with globally routable IP addresses behind your system and are
not NATing at your system, responses to out bound requests will come
back in to the same IP that the request originated from. With that in
mind, consider one reply being a 512 byte response, one reply being a 1k
byte response, and one reply being a 20 k byte response. In this case,
one connection will receive 512 bytes, another 1 k byte, and the last 20
k bytes.
I think we can all agree that this is FAR from a load balanced scenario.
However, we do not have any control over the reverse route, this is at
best our providers control. If each link is with a different provider,
there is no way to load balance the traffic back to our system. If, by
chance the links are all with one provider and they are willing to work
with you and you do not have any reverse path filtering in place, the
provider could spread the load across all the links evenly. However,
this is way beyond the scope of "Load Balancing" under Linux, or any
thing else for that matter, and thus is more or less just accepted.
If you would like, I can go in to more depth as to why this does not
work as is and what would have to be done to make this work.
Incidentally, this is also why QoS does not really work well on inbound.
Grant. . . .
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