Is active-active LVS really capable of doubling theoretical bandwidth?

[Michael Spiegle <mike@xxxxxxxxxxxxxxxx>]

I did some reading on active-active and while I think its a great idea,
I didn't quite understand how it was capable of doubling the throughput
as mentioned in the PDF document.  Here's how I see it:

Lets say you have an active-active LVS pair.  Each individual LVS has a
gigabit fiber card in it.  Since an active-active configuration should
be able to utilize both cards at the same time, you have 2gbit of
THEORETICAL bandwidth (1 + 1 = 2).

Now, from what I gather, the switch must send all traffic destined for
your load-balanced service to both LVSs - and the LVSs individually sort
out which traffic they want to service (by means of iptables, or
whatever floats your boat).

Now, lets say you have 2gbit of traffic coming through the switch.  Your
LVSs should theoretically be able to handle this because its
active-active and they each have 1gbit of throughput, right?  But, if
the switch has to send that 2gbit of traffic to each individual LVS so
the LVS can figure out which 1/2 of the traffic it wants to service.....
how on earth does that happen over 1gbit links?


---
Michael Spiegle
mike@xxxxxxxxxxxxxxxx
310.686.4570