From mboxrd@z Thu Jan 1 00:00:00 1970 From: Roberto Spadim Subject: Re: [patch 2/3 v3] raid1: read balance chooses idlest disk for SSD Date: Mon, 2 Jul 2012 01:31:26 -0300 Message-ID: References: <20120702010840.197370335@kernel.org> <20120702011031.890864816@kernel.org> <20120702030245.GB29770@kernel.org> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Return-path: In-Reply-To: <20120702030245.GB29770@kernel.org> Sender: linux-raid-owner@vger.kernel.org To: Shaohua Li Cc: linux-raid@vger.kernel.org, neilb@suse.de, axboe@kernel.dk List-Id: linux-raid.ids for SSD without inteligent parts (cache and queue) i think this could works nice... (at least in theory) for USB sticks and microsd cards may work too... 2012/7/2 Shaohua Li : > On Sun, Jul 01, 2012 at 11:13:42PM -0300, Roberto Spadim wrote: >> nice =) very very nice =) >> maybe to get better than this... select the disk with min(pending time) >> >> time could be estimated with something like: >> (distance * time/distance unit) + (blocks to read/write * time to >> read/write 1 block) + (non sequencial penalty time) > > I didn't think there is way to measure request time. Disks support NCQ, they > can dispatch several requests at one time and finish them almost at the same > time. I used to measure this time (to make CFQ ioscheduler self tune), but > failed. > > Thanks, > Shaohua > -- > To unsubscribe from this list: send the line "unsubscribe linux-raid" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html -- Roberto Spadim Spadim Technology / SPAEmpresarial