On Fri, 28 Apr 2006 11:28:01 -0400
Greg Troxel <gdt@ir.bbn.com> wrote:

> I've measured (very roughly) on a modern recent P4
>  
> 70 MB/s dd from raw disk
> 59 MB/s dd from 4 GB file in filesystem on disk
> 57 MB/s dd from 'raw disk' in domU
> 
> So in my case it was slower, but not a big deal.

What other, more precise way can be used to meassure drives performance ?
I am thinking of simulating a typical web/mysql/email system's read/write operations.
Running dd gives you an idea of performance when creating one single file
but this is not really what happens on hosting enviroment.
Would writing of a script that runs in a timed loop with multiple dd operations on small files
give a more accurate picture of how the performance gets affected? 

Cheers and thanks
Marcin.