Re: [Scst-devel] Integration of SCST in the mainstream Linux kernel

David Dillow
2008-01-31T18:12:26Z

On Thu, 2008-01-31 at 18:08 +0100, Bart Van Assche wrote:
> If anyone has a suggestion for a better test than dd to compare the
> performance of SCSI storage protocols, please let it know.

xdd on /dev/sda, sdb, etc. using -dio to do direct IO seems to work
decently, though it is hard (ie, impossible) to get a repeatable
sequence of IO when using higher queue depths, as it uses threads to
generate multiple requests.

You may also look at sgpdd_survey from Lustre's iokit, but I've not done
much with that -- it uses the sg devices to send lowlevel SCSI commands.

I've been playing around with some benchmark code using libaio, but it's
not in generally usable shape.

xdd:
http://www.ioperformance.com/products.htm

Lustre IO Kit:
http://manual.lustre.org/manual/LustreManual16_HTML/DynamicHTML-20-1.html
--
Dave Dillow
National Center for Computational Science
Oak Ridge National Laboratory
(865) 241-6602 office