Are large RAID stripe sizes useful with FreeBSD?
Peter Schuller
peter.schuller at infidyne.com
Tue Apr 1 18:03:04 UTC 2008
> 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 raid
and not with FreeBSD) is with concurrent small reads (small = seek is the
dominant cost) on top of a device of many drives. In these cases you want to
minimize the chance that a particular read will span multiple stripes, such
that only a single drive will take a seek hit for a given request. This in
turn maximizes actual physical concurrency when under high load (=high
incoming request concurrency).
--
/ Peter Schuller
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