From owner-freebsd-hackers@FreeBSD.ORG Thu Jan 17 23:04:16 2013 Return-Path: Delivered-To: freebsd-hackers@freebsd.org Received: from mx1.freebsd.org (mx1.FreeBSD.org [8.8.178.115]) by hub.freebsd.org (Postfix) with ESMTP id A2531C23 for ; Thu, 17 Jan 2013 23:04:16 +0000 (UTC) (envelope-from wojtek@wojtek.tensor.gdynia.pl) Received: from wojtek.tensor.gdynia.pl (wojtek.tensor.gdynia.pl [188.252.31.196]) by mx1.freebsd.org (Postfix) with ESMTP id 85004AF3 for ; Thu, 17 Jan 2013 23:04:15 +0000 (UTC) Received: from wojtek.tensor.gdynia.pl (localhost [127.0.0.1]) by wojtek.tensor.gdynia.pl (8.14.5/8.14.5) with ESMTP id r0HN4CwQ006216; Fri, 18 Jan 2013 00:04:12 +0100 (CET) (envelope-from wojtek@wojtek.tensor.gdynia.pl) Received: from localhost (wojtek@localhost) by wojtek.tensor.gdynia.pl (8.14.5/8.14.5/Submit) with ESMTP id r0HN4BNd006213; Fri, 18 Jan 2013 00:04:12 +0100 (CET) (envelope-from wojtek@wojtek.tensor.gdynia.pl) Date: Fri, 18 Jan 2013 00:04:11 +0100 (CET) From: Wojciech Puchar To: Rick Macklem Subject: Re: stupid UFS behaviour on random writes In-Reply-To: <103826787.2103620.1358463687244.JavaMail.root@erie.cs.uoguelph.ca> Message-ID: References: <103826787.2103620.1358463687244.JavaMail.root@erie.cs.uoguelph.ca> User-Agent: Alpine 2.00 (BSF 1167 2008-08-23) MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII; format=flowed X-Greylist: Sender passed SPF test, not delayed by milter-greylist-4.2.7 (wojtek.tensor.gdynia.pl [127.0.0.1]); Fri, 18 Jan 2013 00:04:12 +0100 (CET) Cc: freebsd-hackers@freebsd.org X-BeenThere: freebsd-hackers@freebsd.org X-Mailman-Version: 2.1.14 Precedence: list List-Id: Technical Discussions relating to FreeBSD List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Thu, 17 Jan 2013 23:04:16 -0000 > I'd argue that using an I/O size smaller than the file system block size is > simply sub-optimal and that most apps. don't do random I/O of blocks. > OR > If you had an app. that does random I/O of 4K blocks (at 4K byte offsets), > then using a 4K/1K file system would be better. i can just use raw partition but it isn't about the question. For me it is just clearly suboptimal behavior, but if it "cannot be fixed" then fine. The case is when you store VM images on filesystem and virtual machine issues writes. Quite common case.