[CentOS] partitioning order and IO performance

John R Pierce pierce at hogranch.com
Wed Dec 23 18:29:42 UTC 2009


Ross Walker wrote:
> I think you might be confusing CAV with CLV of optical drives.
> http://en.m.wikipedia.org/wiki/Constant_Angular_Velocity
>   

no, I'm not.     most HD's ('green drives' complicate this some) spin at 
a constant RPM, so the rotational latency is the same on the inner and 
outer tracks, an average of 1/2 turn, about 4mS for a 7200 rpm drive, 
and 2mS for a 15000rpm enterprise drive .   However, the data rate 
changes. so the outer tracks have more data on them, which is read at a 
higher speed in megabytes/second




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