Re: Could RAM possibly be just 3-4 times faster than bare hdd writes and reads? or, is the Linux kernel doing its 'magic' in the bg? or, ...

[Dan Ritter <dsr@randomstring.org>]

Albretch Mueller wrote: 
>  HDDs have their internal caching mechanism and I have heard that the
> Linux kernel uses RAM very effitiently, but to my understanding RAM
> being only 3-4 times faster doesn't make much sense, so I may be doing
> or understanding something not entirely right.
> 
>  does dd actually hit the bare metal drive or is it just reaching the
> disks cache
> 
>  This is what I am consistently getting from my code doing intesive IO
> on the RAM drive:

You're testing cache.

Install the fio package and use that for testing.

-dsr-