Re: [gentoo-user] Software RAID vs "Fake" RAID

[Volker Armin Hemmann]

On Montag 27 April 2009, Andrei Susnea wrote:
> Neil Bothwick wrote:
> > On Mon, 27 Apr 2009 16:18:39 +0400, Yahya Mohammad wrote:
> >> I'm setting up a new desktop machine with RAID 0. The motherboard I
> >> bought supports the so-called "Fake" RAID, which offloads most of the
> >> processing to the system CPU. What are the pros and cons of using this
> >> as opposed to  pure software RAID?
> >
> > The advantage of FakeRAID is that you get to depend on a Windows-only
> > driver that only works with your motherboard and will prevent the RAID
> > working if the motherboard files and you try to connect the drives to a
> > different system. For some reason,this gives Windows users a warm, fuzzy
> > feeling.
>
> Maybe you want pure hardware raid that's a pci(-e) slot that has a chip
> doing all the parity calculations plus a battery keeping data that
> didn't manage to write in case of a power failure. That's the best option.
> For a mb in order to have fake raid capabilities from my understanding
> it has to have a raid chip itself but still most of the calculation is
> done by the CPU.
> Software raid can be done OS dependant... and you don't need any
> hardware or chips for that, it's a form of OS fooling itself instead of
> the MB fooling the OS (fake one).
>
>  From my experience with fake raid 0 on 2 hdd's the speeds would be very
> nice when talking about small files, but for files with 1gb or more the
> writing speed would decrease as the parity calculations get more
> complicated.

there is no parity with raid 0.