From owner-freebsd-fs@FreeBSD.ORG Sun Oct 8 22:38:09 2006 Return-Path: X-Original-To: freebsd-fs@FreeBSD.org Delivered-To: freebsd-fs@FreeBSD.org Received: from mx1.FreeBSD.org (mx1.freebsd.org [216.136.204.125]) by hub.freebsd.org (Postfix) with ESMTP id 4F8A716A40F for ; Sun, 8 Oct 2006 22:38:09 +0000 (UTC) (envelope-from info@fluffles.net) Received: from auriate.fluffles.net (a83-68-3-169.adsl.cistron.nl [83.68.3.169]) by mx1.FreeBSD.org (Postfix) with ESMTP id CBE6B43DA0 for ; Sun, 8 Oct 2006 22:38:01 +0000 (GMT) (envelope-from info@fluffles.net) Received: from destiny ([10.0.0.21]) by auriate.fluffles.net with esmtpa (Exim 4.63 (FreeBSD)) (envelope-from ) id 1GWhHQ-0009vG-Nw; Mon, 09 Oct 2006 00:37:56 +0200 Message-ID: <45297DA2.4000509@fluffles.net> Date: Mon, 09 Oct 2006 00:37:22 +0200 From: "Fluffles.net" User-Agent: Thunderbird 1.5.0.7 (X11/20060917) MIME-Version: 1.0 To: freebsd-fs@FreeBSD.org X-Enigmail-Version: 0.94.0.0 Content-Type: text/plain; charset=ISO-8859-15 Content-Transfer-Encoding: 7bit Cc: Kris Kennaway Subject: Re: 2 bonnies can stop disk activity permanently X-BeenThere: freebsd-fs@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: Filesystems List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Sun, 08 Oct 2006 22:38:09 -0000 Hi Bruce, I'm the "veronica" Arne mentioned in the freebsd-fs mailinglist. Regarding the effectiveness of a higher blocksize, these are my findings: areca RAID5 (8x da, 128KB stripe, default newfs, NCQ enabled) -------Sequential Output-------- ---Sequential Input-- --Random-- -Per Char- --Block--- -Rewrite-- -Per Char- --Block--- --Seeks--- Machine MB K/sec %CPU K/sec %CPU K/sec %CPU K/sec %CPU K/sec %CPU /sec %CPU ARC8xR5 8480 119973 91.3 247178 58.6 67862 17.5 90426 86.9 172490 24.0 120.7 0.5 areca RAID5 (8x da, 128KB stripe, 64KB blocksize newfs, NCQ enabled) -------Sequential Output-------- ---Sequential Input-- --Random-- -Per Char- --Block--- -Rewrite-- -Per Char- --Block--- --Seeks--- Machine MB K/sec %CPU K/sec %CPU K/sec %CPU K/sec %CPU K/sec %CPU /sec %CPU ARC8xR5 8480 128920 97.8 265920 58.9 116787 31.0 103261 97.8 392970 53.8 119.8 0.6 As you can see, the block read increased from ~172MB/s to ~392MB/s, quite significant increase. Also the reqrite speed increased from ~67MB/s to ~116MB/s. Ofcourse these tests are on a brand clean filesystem, which might not tally with real-life crowded filesystems. But at least there is much potential in a higher blocksize, and it would be a shame for it to crash FreeBSD. There are quite a few people who store big files on big RAID arrays; they could profit from a non-crashing FreeBSD with bigger blocksize. Besides, a crashing VFS/Geom isn't all that sexy. ;-) - Veronica