FreeBSD 5.3b7and poor ata performance

[Brad Knowles]

At 2:45 PM -0600 2004-10-25, Scott Long wrote:

>  RAID-0 yes, RAID-10 no, at least not for software RAID.  The machine
>  winds up having to transfer the same data twice across the PCI bus,
>  twice through the controller, etc.  If the controller is on a simple
>  PCI-32/33 bus then it will quickly become saturated.

	I can't speak for GEOM, but my experience with vinum is that 
software RAID, especially RAID-1+0 will totally smoke the bare 
hardware, and will smoke most any PCI hardware RAID controller you 
put it up against.

	Granted, my experience is a few years old, so if you've got any 
more recent data that shows in detail what the current situation is 
and explains why, I'd love to see it.  Until then, I stand by my 
results at <http://www.shub-internet.org/brad/FreeBSD/vinum.html>.

-- 
Brad Knowles, <brad at stop.mail-abuse.org>

"Those who would give up essential Liberty, to purchase a little
temporary Safety, deserve neither Liberty nor Safety."

     -- Benjamin Franklin (1706-1790), reply of the Pennsylvania
     Assembly to the Governor, November 11, 1755

   SAGE member since 1995.  See <http://www.sage.org/> for more info.