[Lustre-discuss] Benchmarking lustre with iozone

[Andreas Dilger]

On Jun 19, 2009  12:32 +0100, Christopher J.Walker wrote:
> I've run some benchmarks on our Lustre setup using iozone, but have 
> stopped before reaching the full potential of our storage due to 
> problems with iozone.
> 
> Iozone seems to hang occasionally. Looking at the source, it looks like 
> it uses UDP packets to tell our worker nodes to start and stop the 
> benchmarks. With debugging turned on, I saw one packet missing in the 
> output when it had hung. Unfortunately, on a network I'm saturating with 
> lustre traffic, the odd packet UDP packet is bound to get lost...
> 
> The iozone author has suggested building a timing network to address 
> this problem - but I can't justify the time and expense to do this.

Usually any cluster will have a separate "administrative" network from
the IO/compute network to ensure that heavy IO/MPI traffic doesn't make
the nodes unreachable by e.g. the job scheduler.  You can run iozone
over the admin network.

Cheers, Andreas
--
Andreas Dilger
Sr. Staff Engineer, Lustre Group
Sun Microsystems of Canada, Inc.