From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1030193AbWGHScR (ORCPT ); Sat, 8 Jul 2006 14:32:17 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S964955AbWGHScR (ORCPT ); Sat, 8 Jul 2006 14:32:17 -0400 Received: from wx-out-0102.google.com ([66.249.82.196]:26073 "EHLO wx-out-0102.google.com") by vger.kernel.org with ESMTP id S964953AbWGHScQ (ORCPT ); Sat, 8 Jul 2006 14:32:16 -0400 DomainKey-Signature: a=rsa-sha1; q=dns; c=nofws; s=beta; d=gmail.com; h=received:message-id:date:from:to:subject:cc:in-reply-to:mime-version:content-type:content-transfer-encoding:content-disposition:references; b=WPTzf40Dp+JOMSA5XJheewaj/u5GeyvyJcHHnkdIkuKkzbbtdPw1tAAEaXE9c0yukPNJOHX0qoyBEKyOCyCYbsE/ho6sNN4AAZelldu4nsCiwty0H4yysXO1zvZr44Yezo8+bDJoWmQvacRDCGCwX5qjLTpQNcCPXjAY6Ql83So= Message-ID: Date: Sat, 8 Jul 2006 13:32:15 -0500 From: "Eric Van Hensbergen" To: "Al Boldi" Subject: Re: [RFC] VFS: FS CoW using redirection Cc: linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org In-Reply-To: <200607082041.54489.a1426z@gawab.com> MIME-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Content-Disposition: inline References: <200607082041.54489.a1426z@gawab.com> Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org On 7/8/06, Al Boldi wrote: > > Copy on Write is a neat way to quickly achieve a semi-clustered system, by > mounting any shared FS read-only and redirecting writes to some perClient > FS. > > Would this redirection be easy to implement into the VFS? > There are a variety of solutions that have been proposed or are available to do this sort of thing. You may want to start by looking at unionfs and mapfs. There are also folks looking at doing this from the block layer (look at the dm-userspace + cowd as well as evms and lvm snapshots). -eric