Network stress test.

Hi there.

First things first, this is nothing to do with the internet or ISP speed, I know what that is, I know what it's doing.

I have a cluster of 128 single board computers running a branch of Debian. I want to run some kind of stress test to ensure they can transfer data (a) to each other and (b) to NAS drives efficiently. These nodes are connected by stacked switches with fibre and lag trunks.

I've tried using the various 'tops available, but there's nothing that will give me (without a load of work) stats from each node point to point.

I could write some python and test the timing of file transfers, socket transfers etc, but I'll end up with a bunch of numbers without any reference.

Can anyone suggest a known 'top, software or service that can stress test the network and give me stats, bottlenecks and where there may be unused bandwidth?

The major caveat, this has to be free or very low cost.

Thanks folks.

Do you know about the iperf tool?

I will look into it now. Thank you.

--- Post updated at 02:47 PM ---

iperf is great for point to point, and I can set off a few nodes, but the server seems to fall over quite often without any errors.