From owner-freebsd-current Fri Dec 17 12:13:43 1999 Delivered-To: freebsd-current@freebsd.org Received: from sabre.velocet.net (sabre.velocet.net [198.96.118.66]) by hub.freebsd.org (Postfix) with ESMTP id 1E12B157E5; Fri, 17 Dec 1999 12:13:41 -0800 (PST) (envelope-from dgilbert@trooper.velocet.net) Received: from trooper.velocet.net (trooper.velocet.net [216.126.82.226]) by sabre.velocet.net (Postfix) with ESMTP id D8E12137FCB; Fri, 17 Dec 1999 15:13:21 -0500 (EST) Received: (from dgilbert@localhost) by trooper.velocet.net (8.9.3/8.9.3) id PAA27440; Fri, 17 Dec 1999 15:13:21 -0500 (EST) (envelope-from dgilbert) From: David Gilbert MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit Message-ID: <14426.39265.260916.742812@trooper.velocet.net> Date: Fri, 17 Dec 1999 15:13:21 -0500 (EST) To: Mike Smith Cc: David Gilbert , freebsd-current@freebsd.org Subject: Re: AMI MegaRAID datapoint. In-Reply-To: <199912172002.MAA00660@mass.cdrom.com> References: <14426.20641.329657.464545@trooper.velocet.net> <199912172002.MAA00660@mass.cdrom.com> X-Mailer: VM 6.75 under 20.4 "Emerald" XEmacs Lucid Sender: owner-freebsd-current@FreeBSD.ORG Precedence: bulk X-Loop: FreeBSD.ORG >>>>> "Mike" == Mike Smith writes: Mike> Try enabling DirectIO and WriteBack if you haven't already. Mike> AMI's RAID5 implementation seems to suffer from rewriting the Mike> entire stripe when you do sub-stripe-sized writes, but I'm not Mike> sure about that yet. Already done. This would explain why 128K stripes are bad. Mike> The Mylex controllers seem to have a small edge in performance, Mike> which may be due to them doing cache-line-sized I/Os (usually Mike> only 8k) in that case. Maybe so, but they also don't seem to support the LVD-enabled versions of the Mylex cards. Dave. -- ============================================================================ |David Gilbert, Velocet Communications. | Two things can only be | |Mail: dgilbert@velocet.net | equal if and only if they | |http://www.velocet.net/~dgilbert | are precisely opposite. | =========================================================GLO================ To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-current" in the body of the message