From owner-freebsd-fs@FreeBSD.ORG Sun Jun 9 10:40:24 2013 Return-Path: Delivered-To: fs@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:1900:2254:206a::19:1]) by hub.freebsd.org (Postfix) with ESMTP id 6CB7EEC8 for ; Sun, 9 Jun 2013 10:40:24 +0000 (UTC) (envelope-from ml@my.gd) Received: from mail-wg0-x234.google.com (mail-wg0-x234.google.com [IPv6:2a00:1450:400c:c00::234]) by mx1.freebsd.org (Postfix) with ESMTP id 0666F1095 for ; Sun, 9 Jun 2013 10:40:23 +0000 (UTC) Received: by mail-wg0-f52.google.com with SMTP id z12so3523073wgg.19 for ; Sun, 09 Jun 2013 03:40:23 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20120113; h=references:mime-version:in-reply-to:content-type :content-transfer-encoding:message-id:cc:x-mailer:from:subject:date :to:x-gm-message-state; bh=9N+NLraiOty4QUjVP50QXOHB1IUkRH1XedUPb5pWWPA=; b=U+Xv4bPY+eCx9APmqFQ7xUyJoWMUhB22lZyK+t/uuSJYHaEHY1oDx1zw/UYF3CybpW U3o39YuJTJZ+Wb17JWhTNscb5GIAEEdWRAHHpivYQDaL7V6Hd1j1Px8w8miaInfQoZqI IwWR96HgdUHWHKOteO3h7JH2wW1lbNUuvuGm6OD8bdYWF8iYgddm8RZXiPzZ98rA/ruH 4yojs7GjS8/UN+9tMLFMW12rCRfRSfNxVprrydjFWZx4n9DOB8NWOHcKIL02bgdK231H LBW/Jb7Yt8EQK/papN6pvwmFVuAtzy2EX96ovUqxNnfBTAfPG3mkWtUoDzk6uO3ZEO2y xHBQ== X-Received: by 10.180.89.140 with SMTP id bo12mr2448667wib.22.1370774423141; Sun, 09 Jun 2013 03:40:23 -0700 (PDT) Received: from [192.168.0.9] (AAubervilliers-652-1-225-231.w83-112.abo.wanadoo.fr. [83.112.232.231]) by mx.google.com with ESMTPSA id ft10sm5532746wib.7.2013.06.09.03.40.21 for (version=TLSv1 cipher=ECDHE-RSA-RC4-SHA bits=128/128); Sun, 09 Jun 2013 03:40:22 -0700 (PDT) References: <16FEF774EE8E4100AD2CAEC65276A49D@multiplay.co.uk> Mime-Version: 1.0 (1.0) In-Reply-To: <16FEF774EE8E4100AD2CAEC65276A49D@multiplay.co.uk> Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: quoted-printable Message-Id: <2AC5E8F4-3AF1-4EA5-975D-741506AC70A5@my.gd> X-Mailer: iPhone Mail (10B144) From: Damien Fleuriot Subject: Re: Changing the default for ZFS atime to off? Date: Sun, 9 Jun 2013 12:39:17 +0200 To: Steven Hartland X-Gm-Message-State: ALoCoQlUgO9W/8K2n7fCgPkhgsxEN6lAa7nkTrhfhhOmwdDOyrT+Z4Hx/WcCBxymmmDLO/JnsiYM Cc: "" X-BeenThere: freebsd-fs@freebsd.org X-Mailman-Version: 2.1.14 Precedence: list List-Id: Filesystems List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Sun, 09 Jun 2013 10:40:24 -0000 On 8 Jun 2013, at 20:54, "Steven Hartland" wrote: > One of the first changes we make here when installing machines > here to changing atime=3Doff on all ZFS pool roots. >=20 > I know there are a few apps which can rely on atime updates > such as qmail and possibly postfix, but those seem like special > cases for which admins should enable atime instead of the other > way round. >=20 > This is going to of particular interest for flash based storage > which should avoid unnessacary writes to reduce wear, but it will > also help improve performance in general. >=20 > So what do people think is it worth considering changing the > default from atime=3Don to atime=3Doff moving forward? >=20 > If so what about UFS, same change? >=20 I strongly oppose the change for reasons already raised by many people regar= ding the mbox file. Besides, if atime should default to off on 2 filesystems and on on all other= s, that would definitely create confusion. Last, I believe it should be the admin's decision to turn atime off, just li= ke it is his decision to turn compression on. Don't mistake me, we turn atime=3Doff on every box, every filesystem, even o= n Mac's HFS. Yet I believe defaulting it to off is a mistake.=