From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757404AbYDBEv6 (ORCPT ); Wed, 2 Apr 2008 00:51:58 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751273AbYDBEvv (ORCPT ); Wed, 2 Apr 2008 00:51:51 -0400 Received: from smtp.nokia.com ([192.100.122.230]:20570 "EHLO mgw-mx03.nokia.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751257AbYDBEvu (ORCPT ); Wed, 2 Apr 2008 00:51:50 -0400 Message-ID: <47F30FDD.5080003@yandex.ru> Date: Wed, 02 Apr 2008 07:47:25 +0300 From: Artem Bityutskiy User-Agent: Thunderbird 2.0.0.12 (X11/20080226) MIME-Version: 1.0 To: Willy Tarreau CC: "H. Peter Anvin" , Andi Kleen , Tomasz Chmielewski , LKML , penberg@cs.helsinki.fi, =?UTF-8?B?SsO2cm4gRW5nZWw=?= , ext-adrian.hunter@nokia.com, jwboyer@gmail.com Subject: Re: UBIFS vs Logfs (was [RFC PATCH] UBIFS - new flash file system) References: <47F1EC20.6050600@wpkg.org> <47F1F644.4060000@yandex.ru> <878wzx25s7.fsf@basil.nowhere.org> <47F21B47.4000206@yandex.ru> <47F26278.5070009@zytor.com> <20080401212652.GD23796@1wt.eu> In-Reply-To: <20080401212652.GD23796@1wt.eu> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit X-OriginalArrivalTime: 02 Apr 2008 04:51:27.0875 (UTC) FILETIME=[360DB530:01C8947D] X-Nokia-AV: Clean Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Willy Tarreau wrote: >> Well, even auto-levelling storage should benefit from a filesystem which >> minimizes the total number of flash sectors churned, which means doing >> as few writes as possible and to large, contiguous sections. > > Exactly. At exosec, we ship one appliance which writes statistics to a > partition on a compactflash every 5 minutes. We preferred to go with JFFS2 > exactly because of this reason. We never had any problem proceeding this way. > I'm not sure if it would have been the same with ext2 though. > Yes, as I agreed in a previous mail this may make sense in some cases. But in general it is not a good approach. Basically, it is wastage of resources. Indeed, first the firmware on MMC/SD/etc makes efforts to make flash look like a block device. It gives you in-place updates, but by cost of performance and reliability. Then you just drop this nice property, and use JFFS2, which assumes it has only out-of-place updates. But if this solves the task you have - fine! -- Best Regards, Artem Bityutskiy (Артём Битюцкий)