On Sep 16, 2010, at 12:33 PM, Marty Scholes wrote: > David Dyer-Bennet wote: >> Sure, if only a single thread is ever writing to the >> disk store at a time. >> >> This situation doesn't exist with any kind of >> enterprise disk appliance, >> though; there are always multiple users doing stuff. > > Ok, I'll bite. > > Your assertion seems to be that "any kind of enterprise disk appliance" will > always have enough simultaneous I/O requests queued that any sequential read > from any application will be sufficiently broken up by requests from other > applications, effectively rendering all read requests as random. If I follow > your logic, since all requests are essentially random anyway, then where they > fall on the disk is irrelevant.
Allan and Neel did a study of this for MySQL. http://www.youtube.com/watch?v=a31NhwzlAxs -- richard -- OpenStorage Summit, October 25-27, Palo Alto, CA http://nexenta-summit2010.eventbrite.com Richard Elling rich...@nexenta.com +1-760-896-4422 Enterprise class storage for everyone www.nexenta.com _______________________________________________ zfs-discuss mailing list zfs-discuss@opensolaris.org http://mail.opensolaris.org/mailman/listinfo/zfs-discuss
