Re: Benchmarks: Linux Kernel RAID vs a Hardware RAID setup

["Keld Jørn Simonsen" <keld@dkuug.dk>]

On Mon, Jul 21, 2008 at 12:55:23PM -0400, Bill Davidsen wrote:
> Keld Jørn Simonsen wrote:
> >On Tue, Jul 15, 2008 at 10:40:26PM +0400, Brad Campbell wrote:
> >  
> >>Keld Jørn Simonsen wrote:
> >>
> >>    
> >>>I would also welcome test with mobo HW RAID - Many mobo's today come
> >>>with some HW raid functionality, and many people would be in the
> >>>situation of whether to choose a HW or SW configuration.
> >>>      
> >>Do you have some pointers for information on motherboards that come with 
> >>hardware raid? I'd be interested to have a look at them. I've certainly 
> >>seen plenty of "fakeraid" systems, but I've not yet come across hardware 
> >>raid on an MB.
> >>    
> >
> >It is possible that I am thinking of what you call fakeraid.
> >  
> 
> I like "firmware raid" better, but the bottom line here is that the raid 
> is still done in the system CPU. These often have little or no hardware 
> support, such as cache so that multiple drives can be written without 
> passing the data through the system bus more than once (and chancing 
> change while that happens).

OK, if the definition on these controllers is that they must have support
from the OS, then I think most of the mobos today come with hardware
raid, that is there needs to be no support in Linux for this. Everything
is set up via the bios, and from the linux kernel it looks like an
ordinary disk.

Best regards
keld
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