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=-5.3 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,NICE_REPLY_A,SPF_HELO_NONE, SPF_PASS,USER_AGENT_SANE_1 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 CBAD8C48BCF for ; Wed, 9 Jun 2021 18:05:27 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id AFC05613DA for ; Wed, 9 Jun 2021 18:05:27 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231901AbhFISHU (ORCPT ); Wed, 9 Jun 2021 14:07:20 -0400 Received: from mail-pf1-f180.google.com ([209.85.210.180]:46844 "EHLO mail-pf1-f180.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229527AbhFISHU (ORCPT ); Wed, 9 Jun 2021 14:07:20 -0400 Received: by mail-pf1-f180.google.com with SMTP id u126so15057804pfu.13; Wed, 09 Jun 2021 11:05:25 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:subject:to:cc:references:from:message-id:date :user-agent:mime-version:in-reply-to:content-language :content-transfer-encoding; bh=tsG2vaYvQdsKPU22yVSS/01hRddm/EYSOLT0Jl+RAWg=; b=NdIVcZXG1ZTfKccG5eX1Z8CMUwAnfD4ZtJGT71isAQVbHtavoLxmAanMQR6pWdHLSx 8U4U0VFaaYZ4KRamr+0vPpjEB5tmwBBY2khpVnMGQjVRNiUPCvA9+SUhp9xipaKsMFLg 5NiFoxKBK6wK9Fs3wS6FYyzibOrI8nZ34Vw0FogMf1E/eUTgeP3JBbbUrX1+MHSwUK+1 jXdU6s/kY9oKZVMCI72/tKsbWRSJnoE9/vBLctsyHKlQ8h2OojAIIrPvYKKb8tkvl47n 8651rVEAiXcEvFD59yejYEif5Povu5WC4kLGGYF4Fr8kNb8LwTzyP9xX71Uq3kch9WeO q5pg== X-Gm-Message-State: AOAM530nbp5qbDDuq3macelzFyvHc2lQuAEy3nBYyogZPtwSWW0URtF/ h++/zfYyqDH/WK3CDNXPDMtfk+tXU7M= X-Google-Smtp-Source: ABdhPJwiyuIter/swQY3pmVDFdPLJluOoHfavogqfTx6tTfv6Cz1YMd5zHC5FpTpzhrMGj7ZqDZ2bg== X-Received: by 2002:a63:fc06:: with SMTP id j6mr933048pgi.226.1623261924921; Wed, 09 Jun 2021 11:05:24 -0700 (PDT) Received: from [192.168.3.217] (c-73-241-217-19.hsd1.ca.comcast.net. [73.241.217.19]) by smtp.gmail.com with ESMTPSA id x20sm219024pfu.205.2021.06.09.11.05.23 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Wed, 09 Jun 2021 11:05:24 -0700 (PDT) Subject: Re: [LSF/MM/BPF TOPIC] durability vs performance for flash devices (especially embedded!) To: Ric Wheeler , lsf-pc@lists.linux-foundation.org Cc: Linux FS Devel , linux-block@vger.kernel.org References: <55d3434d-6837-3a56-32b7-7354e73eb258@gmail.com> From: Bart Van Assche Message-ID: <0e1ed05f-4e83-7c84-dee6-ac0160be8f5c@acm.org> Date: Wed, 9 Jun 2021 11:05:22 -0700 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:78.0) Gecko/20100101 Thunderbird/78.10.2 MIME-Version: 1.0 In-Reply-To: <55d3434d-6837-3a56-32b7-7354e73eb258@gmail.com> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: linux-block@vger.kernel.org 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? More information is available in this paper: https://dl.acm.org/doi/pdf/10.1145/3458336.3465300. Thanks, Bart.