From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-5.8 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, SPF_HELO_NONE,SPF_PASS autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 58A2CC48BD1 for ; Wed, 9 Jun 2021 18:30:45 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 405BC613D5 for ; Wed, 9 Jun 2021 18:30:45 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229976AbhFIScj (ORCPT ); Wed, 9 Jun 2021 14:32:39 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:35980 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229578AbhFISch (ORCPT ); Wed, 9 Jun 2021 14:32:37 -0400 Received: from casper.infradead.org (casper.infradead.org [IPv6:2001:8b0:10b:1236::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 2F429C061574; Wed, 9 Jun 2021 11:30:42 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=casper.20170209; h=In-Reply-To:Content-Type:MIME-Version: References:Message-ID:Subject:Cc:To:From:Date:Sender:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description; bh=MjblxCUCOzYHrNducYPCvaRb+3zgVqvJu23vUfKX0+k=; b=c5rt3jzGtTLNFja84l9vIEupml eGOEFlvj9dNmIfk+6Cwy9PcL/LQVt3cMEVZtSmnByl1QZEO6YIPYfa6AB6/PqIFaAuyIwlo9D06/W s3SEiMt2QEDk6eHyiUM6BulEH6DNkGAVHJ/kc95mjKQh64MJQNFrSkZqF5H12dAXEqP2WzzfoYCCI 7bRbx6/GMAyC8S+P5A4/fxJwlOWib2T27rZw/L75Fav5lwUYJ2AJ5bnCDsH+RhyhLExhggdOBHs5K v9nmZGEQbLijJOgIBFIxLpuPUDFaJFl867U1Cxcs1vgq+hffNi3AARq4+T7ArTxC6jvyumMy+ltho xFW/g8Cg==; Received: from willy by casper.infradead.org with local (Exim 4.94 #2 (Red Hat Linux)) id 1lr2xw-000nJ2-9z; Wed, 09 Jun 2021 18:30:14 +0000 Date: Wed, 9 Jun 2021 19:30:12 +0100 From: Matthew Wilcox To: Bart Van Assche Cc: Ric Wheeler , lsf-pc@lists.linux-foundation.org, Linux FS Devel , linux-block@vger.kernel.org Subject: Re: [LSF/MM/BPF TOPIC] durability vs performance for flash devices (especially embedded!) Message-ID: References: <55d3434d-6837-3a56-32b7-7354e73eb258@gmail.com> <0e1ed05f-4e83-7c84-dee6-ac0160be8f5c@acm.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <0e1ed05f-4e83-7c84-dee6-ac0160be8f5c@acm.org> Precedence: bulk List-ID: X-Mailing-List: linux-block@vger.kernel.org On Wed, Jun 09, 2021 at 11:05:22AM -0700, Bart Van Assche wrote: > On 6/9/21 3:53 AM, Ric Wheeler wrote: > > Consumer devices are pushed to use the highest capacity emmc class > > devices, but they have horrible write durability. > > > > At the same time, we layer on top of these devices our normal stack - > > device mapper and ext4 or f2fs are common configurations today - which > > causes write amplification and can burn out storage even faster. I think > > it would be useful to discuss how we can minimize the write > > amplification when we need to run on these low end parts & see where the > > stack needs updating. > > > > Great background paper which inspired me to spend time tormenting emmc > > parts is: > > > > http://www.cs.unc.edu/~porter/pubs/hotos17-final29.pdf > > Without having read that paper, has zoned storage been considered? F2FS > already supports zoned block devices. I'm not aware of a better solution > to reduce write amplification for flash devices. Maybe I'm missing > something? maybe you should read the paper. " Thiscomparison demonstrates that using F2FS, a flash-friendly file sys-tem, does not mitigate the wear-out problem, except inasmuch asit inadvertently rate limitsallI/O to the device" > More information is available in this paper: > https://dl.acm.org/doi/pdf/10.1145/3458336.3465300. > > Thanks, > > Bart.