From owner-freebsd-questions@FreeBSD.ORG Fri Aug 22 18:24:57 2014 Return-Path: Delivered-To: freebsd-questions@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:1900:2254:206a::19:1]) (using TLSv1 with cipher ADH-AES256-SHA (256/256 bits)) (No client certificate requested) by hub.freebsd.org (Postfix) with ESMTPS id 5CBABEDB for ; Fri, 22 Aug 2014 18:24:57 +0000 (UTC) Received: from mail-qg0-f53.google.com (mail-qg0-f53.google.com [209.85.192.53]) (using TLSv1 with cipher ECDHE-RSA-RC4-SHA (128/128 bits)) (Client CN "smtp.gmail.com", Issuer "Google Internet Authority G2" (verified OK)) by mx1.freebsd.org (Postfix) with ESMTPS id 17E5C341F for ; Fri, 22 Aug 2014 18:24:56 +0000 (UTC) Received: by mail-qg0-f53.google.com with SMTP id z60so7109328qgd.26 for ; Fri, 22 Aug 2014 11:24:49 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20130820; h=x-gm-message-state:subject:mime-version:content-type:from :in-reply-to:date:cc:content-transfer-encoding:message-id:references :to; bh=Pud2SzT60sP+Aykk3UFx+yKvAyer7VzlFufS4HIa/rs=; b=FjRSY3vPEbTvfhMwJIgqRmsdDIMoSPWtpYbSqYZCQUWM762DMXk003d3n71/l1DeC1 9f49Yv5TPDEQqHKKs7gq+BvxJJmqaYI7YG/ky3+aVG/9Db1+ZJfU+XDwQR54gCjMcooQ jps2zY7H+znO7ikS702CQn/JXP8i8VcFXMKXVIcXs57mWmVukBWrQuZ+Szodqdl3GDLO jOTK4vKAJuvvlmd0EuUXLkEe3/+lD9pXVa4EZ3tPl+dnKe3PgDBLEHGpVUL6VR77cSuH OzNb6/RLa0dbV/s7EomE329fcNTAVB8xoNdaEmyKLljcs+B8LfUGzCVk/PeALFe6fCFT BA0Q== X-Gm-Message-State: ALoCoQl+USQUu7u1IOxN/QocMRd1kwsv8HC6r/Bcb4mHjoOfTmZhASGaOkyK/SJM+uiuSGlakD+O X-Received: by 10.229.59.67 with SMTP id k3mr10696831qch.26.1408731889316; Fri, 22 Aug 2014 11:24:49 -0700 (PDT) Received: from mbp-1.thecreativeadvantage.com (mail.thecreativeadvantage.com. [96.236.20.34]) by mx.google.com with ESMTPSA id c8sm56360746qaj.16.2014.08.22.11.24.48 for (version=TLSv1 cipher=ECDHE-RSA-RC4-SHA bits=128/128); Fri, 22 Aug 2014 11:24:48 -0700 (PDT) Subject: Re: solid state drives? Mime-Version: 1.0 (Mac OS X Mail 7.3 \(1878.6\)) Content-Type: text/plain; charset=windows-1252 From: Paul Kraus In-Reply-To: Date: Fri, 22 Aug 2014 14:24:51 -0400 Content-Transfer-Encoding: quoted-printable Message-Id: <7BDE9B34-C73C-4B29-A9BD-53228336BE70@kraus-haus.org> References: <53F22E89.3050005@rcn.com> <53F2399D.5050609@hiwaay.net> <20140822170112.69830ad9@gumby.homeunix.com> To: Daniel Feenberg X-Mailer: Apple Mail (2.1878.6) Cc: RW , freebsd-questions@freebsd.org X-BeenThere: freebsd-questions@freebsd.org X-Mailman-Version: 2.1.18-1 Precedence: list List-Id: User questions List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Fri, 22 Aug 2014 18:24:57 -0000 On Aug 22, 2014, at 12:41, Daniel Feenberg wrote: > I sort of understand that - but does the SSD have the ability to move = unchanged data around to even out the wear? That is, if I fill the drive = with 100GB of never changing files, and then write lots of frequently = changing files to the last 20GB, does this put all the wear on a small = portion of the drive, while most of the drive suffers no wear at all? = Maybe I should do a full backup and restore once a year? Keep in mind that location is not a physical parameter in an SSD. Better = (all today ?) SSD=92s do wear leveling where writes are committed to the = cells that have the lowest write counts. Remember, writes count towards = wear out while I do not think reads do. So an SSD that has write once = data (and archive), should never wear out. So it does not matter where within the block range you write, the SSD = puts it where it wants :-) -- Paul Kraus paul@kraus-haus.org