On Sunday, 30 March 2003 at 18:10:07 +0200, Dag-Erling Smrgrav wrote: > Lukas Ertl <[EMAIL PROTECTED]> writes: >> I'm currently testing with prime stripe sizes, but it doesn't seem to >> help. I additionally added "options AHC_ALLOW_MEMIO" to the kernel, and it >> has raised write performance in the single-disk case (although I'm not >> happy with that one either; I expected a disk on a U160 controller to pump >> out more than ~65MB/s). > > Does the data sheet for your disk indicate that it can in fact write > much faster than that? The speed at which data is actually written > to the media is much lower than the bus speed - the bus speed *has* > to be higher to accomodate multiple devices.
You're touching on one of the real issues here. For optimum transfers, a plex needs large stripes. If you're only doing one transfer at a time (like bonnie does), you'll just pick on individual disks alternately, so the performance can't be much better than a single disk. Do a large number of simultaneous transfers and it will be a different story. Greg -- See complete headers for address and phone numbers
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