* Tyler Retzlaff <rtr@omicron-persei-8.net> [060219 15:28] wrote:
> I've been trying to understand more about disk performance on  
> NetBSD.  So recently I began to perform naive tests
> using dd but the results have me confused perhaps someone can explain.

...

> So what is outsmarting my test?  Is it that in the ffs case the  
> copied data isn't actually being sync()'d?  Or am I being
> defeated by caching somehow?  It's nice that it appears to write as  
> fast as I can read it but if I do large amounts of
> sequential copies (i.e. constantly running for days) I want to know  
> what kind of bottlenecks are going to develop.
> 
> Any guru's have some advice?

FFS will allow async writes for the most part issuing write behind.

This will be faster than being stalled attemping to write to the
raw parition.

--
- Alfred Perlstein
- CTO Okcupid.com / FreeBSD Hacker / All that jazz -