From owner-freebsd-arm@freebsd.org Wed Mar 23 06:43:54 2016 Return-Path: Delivered-To: freebsd-arm@mailman.ysv.freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:1900:2254:206a::19:1]) by mailman.ysv.freebsd.org (Postfix) with ESMTP id 6B18BAD7EC6 for ; Wed, 23 Mar 2016 06:43:54 +0000 (UTC) (envelope-from wlosh@bsdimp.com) Received: from mail-io0-x22a.google.com (mail-io0-x22a.google.com [IPv6:2607:f8b0:4001:c06::22a]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (Client CN "smtp.gmail.com", Issuer "Google Internet Authority G2" (verified OK)) by mx1.freebsd.org (Postfix) with ESMTPS id 31D3F195A for ; Wed, 23 Mar 2016 06:43:54 +0000 (UTC) (envelope-from wlosh@bsdimp.com) Received: by mail-io0-x22a.google.com with SMTP id o5so20385540iod.2 for ; Tue, 22 Mar 2016 23:43:54 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=bsdimp-com.20150623.gappssmtp.com; s=20150623; h=mime-version:sender:in-reply-to:references:date:message-id:subject :from:to:cc; bh=YFtXPUPPFrseJZ7TUv5rE1QtUw0F+wvhUD+TnhL6L7o=; b=AjqfOcyQroS/QyfyFWkJRslrzOCWLbB5vAxAPX6VQxGCX2gsQfWJSWRncTeshFd+UR vsqDKDnL+RR9y1mgK9WrVIiz9PzA3I8S2bw0SmJlxzK8qUs0L6l46srnRmiAL9Sp+bxw tW90xur/D/1LPsf1OsfhpDZ0oEMJ62lPDp+8CI/1l3khyKHDXMxOhC07qxxY4eR1xpXG 6SJnGjf3omiyfAFsN4oKambNLUYdP6a7Sstw7Aq3zJLUwr3Mb7VVIV3znbLxo8PUtL+K /Gha1FM7gJLmKeYO3lbxfhZZ+hbX7yZv41Z/GJ7nCG1HXgF2o8Q0nvhqwr5B9Dhn7Z9J 6xxQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20130820; h=x-gm-message-state:mime-version:sender:in-reply-to:references:date :message-id:subject:from:to:cc; bh=YFtXPUPPFrseJZ7TUv5rE1QtUw0F+wvhUD+TnhL6L7o=; b=BAk54DyTPblavp9wF70fpZOo+g6Pauatkh6hiy3pPwvWJLL9oh9EVQSsd9PwmNJAPg pjiDU8ZF0WekZEjSJWj8tUf+58P2Atxj7TNUj6hdAwwE8Lx2xb2cCbfzEvx4S6Oltkop 29NvDoLgL1dGvfsKCOrwvhQdL278d0rQGKZ5Bxlqj3wrd7fzB3eN58jeGkv+XXYws3ns AG34IEHBO9U8VvqyFUXRpa4+TJ5gVUNleeqMkzXBWmir2+mHGmHkz1hvo4yBLM/NoD8v z4NMByHq7FRnG29/ru+Zk4tMqhjuTrYUJ2ee/aLWaYQduqb2bzgwd4QneO4cPYyBxGZE GNww== X-Gm-Message-State: AD7BkJJ8GW0HENo0ZczQmq/NJrgMmbvtAK/WI7K5xjaF+9XBlnlzehrtvEQ1SVWHlmn9b5Q8J47qxYCHYhnMnA== MIME-Version: 1.0 X-Received: by 10.107.14.209 with SMTP id 200mr1609577ioo.73.1458715433618; Tue, 22 Mar 2016 23:43:53 -0700 (PDT) Sender: wlosh@bsdimp.com Received: by 10.36.65.230 with HTTP; Tue, 22 Mar 2016 23:43:53 -0700 (PDT) X-Originating-IP: [50.253.99.174] In-Reply-To: References: <20160321175952.GA83908@www.zefox.net> <1458586884.68920.96.camel@freebsd.org> <20160321221153.GB83908@www.zefox.net> <1458600070.68920.107.camel@freebsd.org> <20160322032832.GC83908@www.zefox.net> <20160322062635.GD64087@server.rulingia.com> Date: Wed, 23 Mar 2016 00:43:53 -0600 X-Google-Sender-Auth: 0f72gJTd_QxpYt8x5UhtEiTTYSo Message-ID: Subject: Re: Effect of partitioning on wear-leveling From: Warner Losh To: Jia-Shiun Li Cc: "freebsd-arm@freebsd.org" Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: quoted-printable X-Content-Filtered-By: Mailman/MimeDel 2.1.21 X-BeenThere: freebsd-arm@freebsd.org X-Mailman-Version: 2.1.21 Precedence: list List-Id: "Porting FreeBSD to ARM processors." List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Wed, 23 Mar 2016 06:43:54 -0000 On Tue, Mar 22, 2016 at 6:11 AM, Jia-Shiun Li wrote: > On Tue, Mar 22, 2016 at 2:26 PM, Peter Jeremy wrote: > > > On 2016-Mar-21 21:47:39 -0600, Warner Losh wrote: > > >So let=E2=80=99s do the math. 512MB cards tended to have write speeds = of maybe > > 6MB/s. > > >At 6MB/s, that=E2=80=99s about 518MB/day, or one drive write per day. = Most SD > > cards, > > > > I think you dropped some zeroes there. 6MB/s =3D=3D 518,400MB/day =3D= =3D > > 518GB/day. > > That's 1000 drive writes/day - which is non-trivial. > Yes, I must have. I think I must be misremembering the speed. Also, DD spee= d on the 512MB drives I just tried is closer to 3MB/s and writes through the file system are closer to 1MB for big writes and 500k for small writes... Still that's not enough of difference to make up for the while error. Maybe a factor of 10? > > > btw at the days of 512MB cards they are mostly made of SLC nand flash, > some were beginning to transition to MLC. They are different from TLC the= se > days in terms of endurance. That may explain it. SLC parts generally were good for 50k or 100k cycles, while MLC parts are good for 2k-5k. TTLC parts maybe 1k. The 1 drive write per da= y drives generally are at the low end of MLC or the high end of TLC. So that's another factor of 100 there maybe? Warner