On 31/05/2009 18:19, Goswin von Brederlow wrote:

John Robinson [off-list ref] writes:

quoted

Clearly when you're doing this over 4 drives you can have ~400
seeks/second but that's still limiting you to ~400 reads/second for
smallish block sizes.

Note that that only holds true for writes or multithreaded reads.
Reading from a single thread will randomly pick one drive (depending
on where it wants to read), wait for it to seek, read one block of
data and repeat. So you get the speed of a single drive no matter how
many drives there are in the raid.

Sure, that's why I said "can", but I thought iozone was multi-threaded. 
Maybe it needs an option specified, in which case using more threads 
than there are discs would be a good idea.

Cheers,

John.