>If the performance of the outer tracks is better than the performance of the >inner tracks due to limitations of magnetic density or rotation speed (not >being limited by the head speed or bus speed), then the sequential >performance of the drive should increase as a square function, going toward >the outer tracks. c = pi * r^2
Decrease because the outer tracks are the lower numbered tracks; they have the same density but they are larger. >So, small variations of sequential performance are possible, jumping from >track to track, but based on what I've seen, the maximum performance >difference from the absolute slowest track to the absolute fastest track >(which may or may not have any relation to inner vs outer) ... maximum >variation on-par with 10% performance difference. Not a square function. I've noticed a change of 50% in speed or more between the lower and the higher numbers. (60MB to 30MB) In benchmark land, they do short-stroke disks for better performance; I believe the Pillar boxes do similar tricks under the covers (if you want more performance, it gives you the faster tracks) Casper _______________________________________________ zfs-discuss mailing list zfs-discuss@opensolaris.org http://mail.opensolaris.org/mailman/listinfo/zfs-discuss
