RAID 5 stripe size

[Stijn Hoop]

Hi,

On Thu, Aug 05, 2004 at 03:02:25PM +0800, H. Sandring wrote:
> Is there an intelligent way of choosing the stripe size of a RAID 5
> array?

From man vinum:

"For optimum performance, stripes should be at least 128 kB in size: anything
smaller will result in a significant increase in I/O activ- ity due to mapping
of individual requests over multiple disks.  The performance improvement due
to the increased number of concurrent transfers caused by this mapping will
not make up for the performance drop due to the increase in latency.  A good
guideline for stripe size is between 256 kB and 512 kB.  Avoid powers of 2,
however: they tend to cause all superblocks to be placed on the first subdisk."

I expect this to be true for non-vinum RAID-5 volumes as well.

HTH,

--Stijn

-- 
The most reliable proof that there are extraterrestrial intelligent
lifeforms out there is that nobody actually tries to get in contact
with us.
		-- Dirk Mueller
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