[rescue] Any Minneapolis area listers ?

[Charles Shannon Hendrix]

Wed, 10 Jan 2007 @ 02:57 -0500, der Mouse said:

> If you're going for low price, why use "hardware" (usually really
> firmware) RAID at all?  Why not go with software RAID?

Software RAID puts all of the RAID overhead on the host.

If you have a good RAID controller, that overhead happens on the
controller instead, which offloads work from your host bus.

Just for example, mirroring:

If I write 10MB in reality my computer must write 20MB since it has to
do a write to each side of the mirror.

By contrast, if I'm using a RAID controller, the mirror RAID I/O happens
on that controller, so my host bus only has to do the 10MB.

Naturally to get the benefit of this the RAID controller needs to be
fast enough to handle the overhead without delaying your host, but some
fairly fast RAID controllers can be had for relatively low prices now.

-- 
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