From owner-freebsd-performance@FreeBSD.ORG Tue Oct 19 21:02:43 2004 Return-Path: Delivered-To: freebsd-performance@freebsd.org Received: from mx1.FreeBSD.org (mx1.freebsd.org [216.136.204.125]) by hub.freebsd.org (Postfix) with ESMTP id 98D7316A4CF for ; Tue, 19 Oct 2004 21:02:43 +0000 (GMT) Received: from cenn.mc.mpls.visi.com (cenn.mc.mpls.visi.com [208.42.156.9]) by mx1.FreeBSD.org (Postfix) with ESMTP id 6C0AA43D48 for ; Tue, 19 Oct 2004 21:02:43 +0000 (GMT) (envelope-from krishopper@smtp-in.cybernetik.net) Received: from smtp-in.cybernetik.net (unknown [208.42.117.145]) by cenn.mc.mpls.visi.com (Postfix) with ESMTP id C35E18C68; Tue, 19 Oct 2004 16:02:42 -0500 (CDT) Received: by smtp-in.cybernetik.net (Postfix, from userid 1004) id EAE7511451; Tue, 19 Oct 2004 16:02:41 -0500 (CDT) Date: Tue, 19 Oct 2004 16:02:41 -0500 From: Kristofer Pettijohn To: Jo?o Carlos Mendes Lu?s Message-ID: <20041019210241.GB80878@cybernetik.net> References: <20041019193501.GC78974@cybernetik.net> <41756EBF.3010008@jonny.eng.br> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <41756EBF.3010008@jonny.eng.br> User-Agent: Mutt/1.5.6i cc: freebsd-performance@freebsd.org Subject: Re: Disk I/O Performance X-BeenThere: freebsd-performance@freebsd.org X-Mailman-Version: 2.1.1 Precedence: list List-Id: Performance/tuning List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Tue, 19 Oct 2004 21:02:43 -0000 On Tue, Oct 19, 2004 at 04:45:03PM -0300, Jo?o Carlos Mendes Lu?s wrote: > I'd say that you have to check which CCD chunk size is best for > your needs. The manual for vinum recommends avoiding chunk sized to a > power of two, which is probably the first big mistake of everybody. I've tried a wide range of chunk sizes, from 128kB to 64MB.. also have been avoiding powers of 2. > Try mounting with option noatime, if you haven't already. And use > the largest block size possible when formatting. Last time I read about > there was a limit of 16384, but I would expect better performance for > large file with 64k blocks (and 8k frags). The largest block size is 64k, and I have done that as well. > If you don't have a need for safety on the files, you could try > mount async and measure if it suits better you need for performance than > softupdates. Sometimes softupdates is faster, and it is always safer. Unfortunately, the files do need a bit of safety.I did think about async, but I fear the worst to happen. Kristofer