[Beowulf] file IO benchmark

[Toon Knapen]

Joachim Worringen wrote:
> 
> Would running some sort of benchmark really help you (or the customer)
> only because it is well known? I/O performance depends very much on the
> access style and pattern, and the numbers that a benchmark delivers do
> not necessarily reflect what your applications really do.
> 


Our applications are not _that_ sensitive to I/O performance. We're
mainly streaming blocks of a matrix temporarily on disk for reading them
back into memory later on. So pure bandwith is the most important. Which
bench would you advise?

The problem is that our parallel direct out-of-core solver thus needs to
store tmp data on disk. We already encountered problems when people are
using one global NFS mounted filesystem for storing the tmp data of all
nodes in the parallel run. Of course this results in continuous
conflicts on the (slow) ethernet network and a disk trying to stream
multiple big files at the same time. Requesting users to run this
'standard' benchmark will enable us also to detect these kind of situations.

toon