Once upon a time, Samuel Sieb <samuel(a)sieb.net> said:
If you have two gigabit interfaces and a managed switch, you can
also team the interfaces for double the bandwidth. Still much
cheaper than going to 10Gb.
You do not get double the bandwidth from a LAG, except under the most
ideal circumstances; you probably get an increase in overall traffic,
but usually not at all for something like NFS (which uses a single TCP
socket for communication). LAGs don't balance or round-robin traffic;
they hash some selection of packet info (sometimes just
source/destination MAC, sometimes adding IP, sometimes also TCP/UDP
src/dest port) and select a LAG member to use based on the hash. All
packets of a single stream go down the same LAG member, because
otherwise you introduce jitter and out-of-order packet arrival.
Also, 10G has lower latency than 1G, which helps NFS performance as
well.
--
Chris Adams <linux(a)cmadams.net>