On Wed, 21 Oct 2009, David Dyer-Bennet wrote:
Device performance should be specified as a minimum assured level of performance and not as meaningless "peak" ("up to") values. I repeat: peak values are meaningless.Seems a little pessimistic to me. Certainly minimum assured values are the basic thing people need to know, but reasonably characterized peak values can be valuable, if the conditions yielding them match possible application usage patterns.
Agreed. It is useful to know minimum, median, and peak values. If there is a peak, it is useful to know how long that peak may be sustained. Intel's specifications have not characterized the actual performance of the device at all.
The performance characteristics of rotating media are well understood since they have been observed for tens of years. From this we already know that the "peak" performance of a hard drive does not have much to do with its steady-state performance since the peak performance is often defined by the hard drive cache size and the interface type and clock rate.
Bob -- Bob Friesenhahn bfrie...@simple.dallas.tx.us, http://www.simplesystems.org/users/bfriesen/ GraphicsMagick Maintainer, http://www.GraphicsMagick.org/ _______________________________________________ zfs-discuss mailing list zfs-discuss@opensolaris.org http://mail.opensolaris.org/mailman/listinfo/zfs-discuss
