My question: What are the chunk and usable storage sizes per stripe for four
discs in RAID-0 on an ICH7R configured for a 128KB "strip"?
raid0 always has 100% usable; configuring it is deciding how much
concurrency you want.
if your writes are 64K and you have 4 disks, your max concurrency would
be at 64K per disk (stripe size in MD), or 256K for a whole stripe.
if you want max bandwidth, but concurrency of 1, you want the 64k write
to busy all the disks, for a 16K stripe size (64K whole-stripe).
with raid5, the main thing additional factor is to try to arrange
"blind" whole-stripe writes if possible. that is, you pay the
read-modify-write penalty unless you write a whole stripe at once:
n-1 * stripe size if you can manage it aligned, or at least several
whole stripes to amortize the reads necessary on the edges...
-
To unsubscribe from this list: send the line "unsubscribe linux-raid" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
