Are large RAID stripe sizes useful with FreeBSD?

[Peter Schuller]

> 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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