From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from proxy.dresearch.de ([87.193.137.100] helo=mail.dresearch.de) by linuxtogo.org with esmtp (Exim 4.72) (envelope-from ) id 1PstP6-000746-AP for openembedded-devel@lists.openembedded.org; Fri, 25 Feb 2011 09:52:00 +0100 Received: from exchange.intern.dresearch.de (owa.xfer-intern.dresearch.de [192.168.32.16]) by mail.dresearch.de (Postfix) with ESMTP id 14263491283; Fri, 25 Feb 2011 09:50:41 +0100 (CET) Received: from [127.0.0.1] ([10.32.10.2]) by exchange.intern.dresearch.de with Microsoft SMTPSVC(6.0.3790.4675); Fri, 25 Feb 2011 09:50:41 +0100 Message-ID: <4D676D60.1040909@dresearch.de> Date: Fri, 25 Feb 2011 09:50:40 +0100 From: Steffen Sledz User-Agent: Mozilla/5.0 (Windows; U; Windows NT 5.1; de; rv:1.9.2.13) Gecko/20101207 Lightning/1.0b2 Thunderbird/3.1.7 MIME-Version: 1.0 To: openembedded-devel@lists.openembedded.org References: <4D53C412.9090804@dresearch.de> <1297339435.2178.23.camel@phil-desktop> <4D53F6FE.80604@windriver.com> In-Reply-To: <4D53F6FE.80604@windriver.com> X-OriginalArrivalTime: 25 Feb 2011 08:50:41.0281 (UTC) FILETIME=[14CEE710:01CBD4C9] Subject: Re: base-files vs. FHS-2.3 X-BeenThere: openembedded-devel@lists.openembedded.org X-Mailman-Version: 2.1.11 Precedence: list Reply-To: openembedded-devel@lists.openembedded.org List-Id: Using the OpenEmbedded metadata to build Distributions List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Fri, 25 Feb 2011 08:52:00 -0000 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: quoted-printable Am 10.02.2011 15:32, schrieb Mark Hatle: > On 2/10/11 6:03 AM, Phil Blundell wrote: >> On Thu, 2011-02-10 at 11:55 +0100, Steffen Sledz wrote: >>> While dealing with the /var subdirs i hit some differences between Fi= lesystem Hierarchy Standard (current FHS-2.3) and the base-files package. >>> >>> One point is that /var/tmp is symlinked to volatile/tmp but according= to the standard this dir contains "Temporary files *preserved between sy= stem reboots* ". >>> >>> Also /var/cache is symlinked to volatile/cache but the standard descr= ibes "The data must remain valid between invocations of the application *= and rebooting the system.* " what i would read in the way that /var/cache= should be persistent too. >>> >>> May be there are other differences. >>> >>> In my opinion the symlinking in base-files is buggy and should be fix= ed. Or am i wrong here? >> >> It probably would be good to have a version of base-files which was >> fully FHS conformant. But there are a significant number of OE target >> systems where it is simply impossible to comply with these requirement= s >> since there is no persistent read/write storage available: the only >> choice is between flash (persistent but read-only) and ramdisk >> (read-write but volatile). =20 >> >> Clearly, placing /var/tmp or /var/cache in a readonly location is >> unlikely to produce any useful results so linking them into volatile/ = is >> the least bad option in that situation. Any change to base-files woul= d >> need to be done with some level of care in order to not break those >> kinds of setups which do work today. I guess it should be a DISTRO >> decision whether or not to adhere to the FHS in this area. >=20 > I echo this. In my experiences the default filesystem should be FHS co= mpliant, > but there must be a variant that works for specific embedded projects t= hat > simply do not have writable storage. >=20 > The ramifications of this are that /var/tmp, /var/cache are both transi= ent over > reboots. Almost all applications will deal with this gracefully, so it= 's not > really an issue. It is something to be aware of though when doing soft= ware > integration and validation that the problems must be able to create tmp= and > cache files over again if the data is not already on the system. >=20 > The important things when following the FHS really are R/O vs R/W suppo= rt, as > well a boot vs run-time. (i.e. things required on '/' vs things that s= hould > live in '/usr'...) Ping! --=20 DResearch Fahrzeugelektronik GmbH Otto-Schmirgal-Str. 3, 10319 Berlin, Germany Tel: +49 30 515932-237 mailto:sledz@DResearch.de Fax: +49 30 515932-299 Gesch=E4ftsf=FChrer: Dr. Michael Weber, Werner M=F6gle; Amtsgericht Berlin Charlottenburg; HRB 130120 B; Ust.-IDNr. DE273952058