[Beowulf] file IO benchmark
James.P.Lux at jpl.nasa.gov
Thu Nov 24 09:11:20 EST 2005
At 01:49 AM 11/24/2005, Toon Knapen wrote:
>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.
Why not something fairly crude like measuring "wall clock" time to
read/write a large file. Do it as a 4 or 5 line shell script.
Or, are there some subtleties in the dynamics that you're trying to capture?
Beowulf mailing list, Beowulf at beowulf.org
To change your subscription (digest mode or unsubscribe) visit http://www.beowulf.org/mailman/listinfo/beowulf
More information about the Beowulf