slice for I/O performance

I heard that some cylinders can be accessed faster than others but not sure they go from cyl #0 to higher cyl# or the other way around. If I am gonna to pick a slice for a raw device, what should it be ? Thanks, Thanh Sent via Deja.com http://www.deja.com/ Before you buy.

Thanh wrote: > > I heard that some cylinders can be accessed faster than others but not > sure they go from cyl #0 to higher cyl# or the other way around. > If I am gonna to pick a slice for a raw device, what should it be ? You will tend to get the best sequential throughput from outer cylinders on modern drives because of cylinder zoning whereby the outer N cylinders each contain more sectors than the next N cylinders and so on. In general seek times, and therefore random I/O, will be best on the center cylinders of the drive because on average less head movement will be required to return the heads from cylinder that you are not interested in to the ones you are. With good caching and a drive that is not being stressed the latter effect is mitigated somewhat by the fact that drives return the heads to a dead cylinder outside the data area if the drive is quiet for a certain period of time so.... it depends. -- Art S. Kagel & Family kagel@erols.com