I had some troubles with my RAID controler and its logical drive... it was
generating ugly failures on the NSS pools caused by bad stripes...

By now, I replaced some hardware, upgraded firmware on the RAID controler,

What I would like to do, is to do some kind of stress test on my storage
system, to verify that no more similar problems will occur...

Is there any known utility (free, if possible) which makes stress testing
over my storage subsystem? From where can I get it?