Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1762007AbZDBV4h (ORCPT ); Thu, 2 Apr 2009 17:56:37 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1754975AbZDBV43 (ORCPT ); Thu, 2 Apr 2009 17:56:29 -0400 Received: from srv5.dvmed.net ([207.36.208.214]:47614 "EHLO mail.dvmed.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754363AbZDBV42 (ORCPT ); Thu, 2 Apr 2009 17:56:28 -0400 Message-ID: <49D5347A.8030403@garzik.org> Date: Thu, 02 Apr 2009 17:56:10 -0400 From: Jeff Garzik User-Agent: Thunderbird 2.0.0.21 (X11/20090320) MIME-Version: 1.0 To: David Rees CC: Andrew Morton , Janne Grunau , Lennart Sorensen , Linus Torvalds , Theodore Tso , Jesper Krogh , Linux Kernel Mailing List Subject: Re: Linux 2.6.29 References: <20090325183011.GN32307@mit.edu> <20090326171148.9bf8f1ec.akpm@linux-foundation.org> <20090326174704.cd36bf7b.akpm@linux-foundation.org> <20090326182519.d576d703.akpm@linux-foundation.org> <20090401210337.GB3797@csclub.uwaterloo.ca> <20090402110532.GA5132@aniel> <20090402090912.cac200bb.akpm@linux-foundation.org> <72dbd3150904020933y515c7185p5726323c430c339b@mail.gmail.com> In-Reply-To: <72dbd3150904020933y515c7185p5726323c430c339b@mail.gmail.com> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit X-Spam-Score: -4.4 (----) X-Spam-Report: SpamAssassin version 3.2.5 on srv5.dvmed.net summary: Content analysis details: (-4.4 points, 5.0 required) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 860 Lines: 22 David Rees wrote: > Either way - forcing the data to be synced to disk a couple times > every second is a hack and causes fragmentation in filesystems without > delayed allocation. Fragmentation really goes up if you are recording > multiple shows at once. Check out posix_fallocate(3). Not appropriate for every situation, might eat additional disk bandwidth... But if you are looking to combat fragmentation, pre-allocation (manual or kernel-assisted) is a relevant technique. Plus, overwriting existing data blocks is a LOT cheaper than appending to a file. fsync's more quickly to disk, too. Jeff -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/