Follow up on my previous post regarding bonding
jal at mdacorporation.com
Mon Sep 15 12:45:21 CDT 2008
> I have two Poweredge 2900-III servers connected to the same
> 2960 switch, each server has a 4Gb etherchannel (bond0)
> connection to the switch.
> When I use iperf to test the transfer rates between the two
> systems it never goes above 944Mbps.
> Does anyone have any advice or has anyone ever gotten this to
> work any better?
> Thank you,
Why do you think it should go faster?
"...generally speaking, modes provide either hot standby or load
Aggregate throughput = sum(ethernets), but max throughput per session =
one ethernet. Four iperfs running concurrently *might* be around 900
Mb/s each, depending on how the bonding is setup. Possibly, you will
only get a total of 900 Mb/s across all 4 iperfs. Read the docs for
Technically, bonding allocates outbound IP frames to an interface, not
to a collection of interfaces. So it can only send one frame at a time.
See section 12.1.1 of the bonding.txt file for a possible fix; your
switch needs to support round-robin (IIRC, Cisco 2960s do not. We tried
once with Linux vs Windows 2k3 and C2960s, but discovered it could not
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