From owner-freebsd-current@FreeBSD.ORG Fri Mar 30 19:36:32 2012 Return-Path: Delivered-To: freebsd-current@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [69.147.83.52]) by hub.freebsd.org (Postfix) with ESMTP id 231A7106564A; Fri, 30 Mar 2012 19:36:32 +0000 (UTC) (envelope-from adrian.chadd@gmail.com) Received: from mail-pb0-f54.google.com (mail-pb0-f54.google.com [209.85.160.54]) by mx1.freebsd.org (Postfix) with ESMTP id DF3788FC08; Fri, 30 Mar 2012 19:36:31 +0000 (UTC) Received: by pbcwz17 with SMTP id wz17so2463544pbc.13 for ; Fri, 30 Mar 2012 12:36:31 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20120113; h=mime-version:sender:in-reply-to:references:date :x-google-sender-auth:message-id:subject:from:to:cc:content-type :content-transfer-encoding; bh=1WQIO0bsUd0yEVHay6CAWvwxJm7a6VHMD12W9ByBPBs=; b=SnxjD3HPo7ZogpZ05ULH54De/NAZNYXC5wEJegTTn55OxsQ7o93Q/YDQ1S8LpPOwkP WvZzB6CSJ9WuUGeJUONynobnNCi2uOWBe0O6qZFbx/LHS8PSEjOqaHpydtOgIq1QDaJs NKm8ozMQCoPcF48CLxA2Y8z6SIjPHK64XEtTkT6HkkrtzIHnXBxtUEWfum6/+ByQQtc9 Rfd98oNG7BIn4oXSz1Sp5mmpumo3iUEIE02DDxrcQAddCVXvAjay0XqruJhgR0AuQMaG 73XfYpBuJ3M9rB8qDV5TVIDSF/sD5jl3V54TyUwWwv/f2X3E1T50XW+2VuPh0cyP0GFC PJqA== MIME-Version: 1.0 Received: by 10.68.204.234 with SMTP id lb10mr31634pbc.98.1333136191274; Fri, 30 Mar 2012 12:36:31 -0700 (PDT) Sender: adrian.chadd@gmail.com Received: by 10.143.19.19 with HTTP; Fri, 30 Mar 2012 12:36:31 -0700 (PDT) In-Reply-To: References: <4F746F1E.6090702@mail.zedat.fu-berlin.de> <4F74BCE8.2030802@vangyzen.net> <20120330.151848.41706133.sthaug@nethelp.no> Date: Fri, 30 Mar 2012 12:36:31 -0700 X-Google-Sender-Auth: H-URYOb56B6ZTKNI2o72qlR-at8 Message-ID: From: Adrian Chadd To: Chris Rees Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: quoted-printable Cc: freebsd-current@freebsd.org, "C. P. Ghost" , sthaug@nethelp.no Subject: Re: Using TMPFS for /tmp and /var/run? X-BeenThere: freebsd-current@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: Discussions about the use of FreeBSD-current List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Fri, 30 Mar 2012 19:36:32 -0000 Let me tell you a story. Someone decided that ext4 could have a decent speed up if it implemented the posix standard for not flushing files on close(). After all, if you needed it to be guaranteed to be written to disk, you would call a flush routine first, before you called close(). So they did this. Then people testing out ext4 discovered that upon crash, their kde/gnome profiles were corrupted. Why? Because KDE/Gnome authors hadn't ever called flush before close(), and they weren't the only ones. They didn't read the standard, they only used the system and fixed bugs whenever their system behaved against their expectations. They didn't notice that the system was being different from the standard. Guess what ext4 did? :) Don't mis-estimate POLA. Adrian On 30 March 2012 10:56, Chris Rees wrote: > On 30 March 2012 17:31, C. P. Ghost wrote: >> On Fri, Mar 30, 2012 at 3:18 PM, =A0 wrote: >>>> > However, if you always want to use tmpfs instead of stable storage, >>>> please do not. =A0Some people expect /tmp to be persistent. =A0This is= why >>>> /etc/defaults/rc.conf has clear_tmp_enable=3D"NO". =A0Changing this wo= uld break >>>> the POLA. >>>> > >>>> This is a mistake. >>>> >>>> The default should be clear_tmp_enable=3D"YES" >>>> if only to uncover those broken configurations that expect /tmp to be >>>> persistent. >>> >>> If you want to break POLA and make a lot of people angry, sure. >>> Otherwise no. >> >> I couldn't agree more. Not clearing /tmp on reboot has been >> the norm for way too long and it is too late to change now. >> It's not just POLA, it also involves deleting data of unaware >> users, and that should be avoided. >> >> Anyone willing to change policy w.r.t. /tmp can do so on their >> own machines. Nothing is preventing them from doing so. >> But by changing defaults, one should err on the side of >> caution and remain conservative, IMHO. > > >From man hier: > > /tmp/ =A0 =A0 =A0temporary files that are not guaranteed to persist acros= s > system reboots > > This assumption that people often make 'People will be astonished by > this'-- I would like to have someone speak up and actually say "Yes, I > use *temporary* directories for long-term storage" rather than the > assumption that they are around. > > Software that assumes this should be fixed, and it won't be until the > bug is exposed (I'll look at eaccelerator-- it probably should store > its cache in /var/db). > > Maintaining the status quo because of some hypothetical scenario isn't > really productive. > > Chris > _______________________________________________ > freebsd-current@freebsd.org mailing list > http://lists.freebsd.org/mailman/listinfo/freebsd-current > To unsubscribe, send any mail to "freebsd-current-unsubscribe@freebsd.org= "