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From: Peter Schuller <peter.schuller@infidyne.com>
To: freebsd-current@freebsd.org,
 d@delphij.net
Date: Tue, 1 Apr 2008 19:05:21 +0100
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Cc: Ivan Voras <ivoras@freebsd.org>
Subject: Re: Are large RAID stripe sizes useful with FreeBSD?
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> Short answer: yes.  Larger stripe sizes would allow better performance
> for continuous read/write.  In theory they will negatively affect small
> size read/write but in practice you will notice that larger stripe size
> would give better performance in almost all cases.

One case where I have used large stripe sizes (though not with hardware rai=
d=20
and not with FreeBSD) is with concurrent small reads (small =3D seek is the=
=20
dominant cost) on top of a device of many drives. In these cases you want t=
o=20
minimize the chance that a particular read will span multiple stripes, such=
=20
that only a single drive will take a seek hit for a given request. This in=
=20
turn maximizes actual physical concurrency when under high load (=3Dhigh=20
incoming request concurrency).

=2D-=20
/ Peter Schuller

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