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Date: Tue, 15 Jan 2013 17:09:23 -0500
From: Karim Fodil-Lemelin <fodillemlinkarim@gmail.com>
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Subject: Re: IBM blade server abysmal disk write performances
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On 15/01/2013 3:55 PM, Adrian Chadd wrote:
> You're only doing one IO at the end. That's just plain silly. There's
> all kinds of overhead that could show up, that would be amortized over
> doing many IOs.
>
> You should also realise that the raw disk IO on Linux is by default
> buffered, so you're hitting the buffer cache. The results aren't going
> to match, not unless you exhaust physical memory and start falling
> behind on disk IO. At that point you'll see what the fuss is about.
>
To put is simply and maybe give a bit more context, here is what we're 
doing:

1) Boot OS (Linux or FreeBSD in this case)
2) dd some image over to the SAS drive.
3) rinse and repeat for X times.
4) profit.

In this case if step 1) is done with Linux we get 100 times more profit. 
I was wondering if we could close the gap.

Karim.