Re: raw Vs kernel aio

Jeff Kalchik wrote: > > On Mon, 09 Mar 1998 22:41:38 -0600, braispa@mail.northgrum.com wrote: > > >Just when I thought I was ready to setup my databases on raw devices I have > >heard that HP does not like kernel i/o. > > > >I am on an HP-9000 model k370. version 10.20 HP-UX. I am using Informix > >dynamic server. Can anyone shed some light on the question of what is the > >best cfhoice for informix on an HP? > > > >-----== Posted via Deja News, The Leader in Internet Discussion ==----- > >http://www.dejanews.com/ Now offering spam-free web-based newsreading > > Check your release notes. I've got 7.23.UC5 running up HP-UX 10.20 on > a K420 (2 processors, 1 gb RAM). KAIO seems to be running just fine. Besides you can still use RAW devices with AIO VPs if they perform better for you. You just define KAIOOFF=1 in the environment when the engine is started and KAIO is turned off and AIO VPs are used for RAW I/O also. Some systems, DG M88K and certain HP platforms (see a post on the subject last week) perform better with AIO VPs others with KAIO. Bottom line: Your mileage may vary. We found that for our platform (DG M88K), using Informix Processor Affinity KAIO is 50% faster than AIO VPs but using external affinity scripts that also affined the AIO VPs; AIO VPs were 100% faster than KAIO using any affinity method! Art S. Kagel