From mboxrd@z Thu Jan 1 00:00:00 1970 From: Stan Hoeppner Subject: Re: Performance question, RAID5 Date: Sun, 30 Jan 2011 14:03:06 -0600 Message-ID: <4D45C3FA.2040900@hardwarefreak.com> References: <20110130094444.68288b0e@natsu> <20110130171533.4c9e236b@natsu> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: QUOTED-PRINTABLE Return-path: In-Reply-To: Sender: linux-raid-owner@vger.kernel.org To: =?ISO-8859-1?Q?Mathias_Bur=E9n?= Cc: Roman Mamedov , CoolCold , Linux-RAID List-Id: linux-raid.ids Mathias Bur=E9n put forth on 1/30/2011 1:41 PM: > Thanks. New results up for those interested: > http://stuff.dyndns.org/logs/bonnie_results.html Three things I notice: 1. You're CPU bound across the board, for all the tests that matter an= yway 2. Because of this, your performance spread is less than 5% across the= board meaning any optimizations are useless 3. Is that a 7 Gigabyte chunk size? That's totally unrealistic. It s= hould be less than 1 MB for almost all workloads. According to those numbers, you can swap SATA controllers and PCIe bus = slot assignments all day long, but you'll gain nothing without a faster CPU. Why are you using a 7 Gigabyte chunk size? And if the other OP was cor= rect about the 768MB stripe cache, that's totally unrealistic as well. And = in real world use, you don't want a high readahead setting. It just wastes buf= fer cache memory for no gain (except maybe in some synthetic benchmarks). --=20 Stan -- To unsubscribe from this list: send the line "unsubscribe linux-raid" i= n the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html