From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: with ECARTIS (v1.0.0; list xfs); Mon, 17 Jul 2006 12:09:03 -0700 (PDT) Received: from smtp107.sbc.mail.mud.yahoo.com (smtp107.sbc.mail.mud.yahoo.com [68.142.198.206]) by oss.sgi.com (8.12.10/8.12.10/SuSE Linux 0.7) with SMTP id k6HJ8oDW023164 for ; Mon, 17 Jul 2006 12:08:50 -0700 Date: Mon, 17 Jul 2006 12:08:27 -0700 From: Chris Wedgwood Subject: Re: file system defragmentation Message-ID: <20060717190827.GA7845@tuatara.stupidest.org> References: <4f52331f050826001612f8e323@mail.gmail.com> <20050826101131.GA24544@ii.uib.no> <4f52331f0508260848782f240a@mail.gmail.com> <43128F82.4010004@tlinx.org> <4312913F.6040205@coremetrics.com> <43311567.3060208@tlinx.org> <5356806.post@talk.nabble.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <5356806.post@talk.nabble.com> Sender: xfs-bounce@oss.sgi.com Errors-To: xfs-bounce@oss.sgi.com List-Id: xfs To: Cosmo Nova Cc: linux-xfs@oss.sgi.com On Mon, Jul 17, 2006 at 12:36:09AM -0700, Cosmo Nova wrote: > If I have a DVR system of 16 channels. They keep writing data to the > disk in pieces of video files. I did some work for someone who does a similar thing (they write 96 channels in parallel and have to be able to do read back up to 32 of them at the same time of something). By default concurrent writes into the same directory will cause the files to get badly interleaved, and trying to get one file per-ag doesn't work so well if the agcount < n-files. I ended up getting them to change their code to preallocate and AFAIK it works very well now (you can throw away any space you over allocate when you're closing the file too).