From owner-freebsd-arm@FreeBSD.ORG Thu Jul 3 06:20:23 2014 Return-Path: Delivered-To: freebsd-arm@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [8.8.178.115]) (using TLSv1 with cipher ADH-AES256-SHA (256/256 bits)) (No client certificate requested) by hub.freebsd.org (Postfix) with ESMTPS id 9B5A9ABA; Thu, 3 Jul 2014 06:20:23 +0000 (UTC) Received: from mail-wg0-x229.google.com (mail-wg0-x229.google.com [IPv6:2a00:1450:400c:c00::229]) (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 EF7E22FB3; Thu, 3 Jul 2014 06:20:22 +0000 (UTC) Received: by mail-wg0-f41.google.com with SMTP id a1so12388320wgh.24 for ; Wed, 02 Jul 2014 23:20:21 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20120113; h=from:message-id:date:reply-to:user-agent:mime-version:to:subject :references:in-reply-to:content-type:content-transfer-encoding; bh=Xger8mFH1ABgJmzlfDkRUnIHxKcSLRYzsfyeaCOWEtc=; b=K5cjfA9XDnmCYNgHnYJUgcIwixkrw99NcpRQda3OPEPe5i1YMyyV0n5M1NBuA9Fg0a EzfscRqZVdM0IzP9pLxds26OJ42sKaW772k1iR71mb7R7YlykbrMEvzZB6xHCYN+cOGP u+yY2S7ctWzGDTxoK5XdF6NyeAP1YeokuFNHfoOUdsXyBDZIy5u3cBrEdAg5L6aYETGc Ng65uyTxKlEFpaRXRaEjbbkAj0lQgLtKJFIwYpDJ/fDlLzGIl4V6yLQf34CpAh7RJMGo HP2Z5hDTSmbXeRbZaFITr9vkAdBhvsMpXs9jbx8ynN+EfoW2zjqlbe8nLFNlZUf3C7vJ 3q7A== X-Received: by 10.180.19.40 with SMTP id b8mr9169469wie.77.1404368421077; Wed, 02 Jul 2014 23:20:21 -0700 (PDT) Received: from [192.168.0.10] (178-83-152-199.dynamic.hispeed.ch. [178.83.152.199]) by mx.google.com with ESMTPSA id gq4sm29581781wib.8.2014.07.02.23.20.19 for (version=TLSv1 cipher=ECDHE-RSA-RC4-SHA bits=128/128); Wed, 02 Jul 2014 23:20:20 -0700 (PDT) From: Mattia Rossi X-Google-Original-From: Mattia Rossi Message-ID: <53B4F621.3040306@gmail.com> Date: Thu, 03 Jul 2014 08:20:17 +0200 Reply-To: mattia.rossi.mate@gmail.com User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:24.0) Gecko/20100101 Thunderbird/24.6.0 MIME-Version: 1.0 To: Anton Shterenlikht , rene@freebsd.org, freebsd-arm@freebsd.org Subject: Re: /tmp, /var/log, /var/tmp as /dev/md - why? References: <201407011046.s61AkJpj006890@mech-cluster241.men.bris.ac.uk> <20140702022042.GG45513@funkthat.com> In-Reply-To: <20140702022042.GG45513@funkthat.com> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit X-BeenThere: freebsd-arm@freebsd.org X-Mailman-Version: 2.1.18 Precedence: list List-Id: "Porting FreeBSD to ARM processors." List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Thu, 03 Jul 2014 06:20:23 -0000 On 02/07/14 04:20, John-Mark Gurney wrote: > Anton Shterenlikht wrote this message on Tue, Jul 01, 2014 at 11:46 +0100: >> >From r.c.ladan@gmail.com Tue Jul 1 11:37:35 2014 >>> 2014-07-01 11:25 GMT+02:00 Anton Shterenlikht : >>> >>>> Why is it a good idea to mount /tmp and some var dirs on memory disks: >>>> >>>> root@raspberry-pi:/usr/ports # df -m >>>> Filesystem 1M-blocks Used Avail Capacity Mounted on >>>> /dev/mmcsd0s2a 14694 777 12742 6% / >>>> devfs 0 0 0 100% /dev >>>> /dev/mmcsd0s1 16 3 13 20% /boot/msdos >>>> /dev/md0 28 4 22 16% /tmp >>>> /dev/md1 14 0 12 0% /var/log >>>> /dev/md2 4 0 4 0% /var/tmp >>>> root@raspberry-pi:/usr/ports # >>>> >>>> Is this about speed or power, or maybe space? >>>> >>>> Mostly write tear because you're using an SD card, and it improves speed >>> too. >> "write tear"? >> Is this a joke, or some technical term? >> I cannot find what it means. > it is a technical term, though I'd be surprised if any SD card had > an issue w/ that anymore... > > write tear is where when writing data, only part of the data gets > written and then you loose power... This is mostly an issue on flash > where you have to erase the data beforey ou can program it... Most > flash now have a layer of indirection so that they copy/write the > data to a new flash block, and then point the block there before > erasing the old data... (kinda like a log FS)... > > Something like this will happen once your SD card is weared off.... grmbl: (da0:umass-sim0:0:0:0): WRITE(10). CDB: 2a 00 00 19 5c 26 00 00 80 00 (da0:umass-sim0:0:0:0): CAM status: SCSI Status Error (da0:umass-sim0:0:0:0): SCSI status: Check Condition (da0:umass-sim0:0:0:0): SCSI sense: MEDIUM ERROR asc:30,0 (Incompatible medium i nstalled) (da0:umass-sim0:0:0:0): Retrying command (per sense data) (da0:umass-sim0:0:0:0): WRITE(10). CDB: 2a 00 00 19 5c 26 00 00 80 00 (da0:umass-sim0:0:0:0): CAM status: SCSI Status Error (da0:umass-sim0:0:0:0): SCSI status: Check Condition (da0:umass-sim0:0:0:0): SCSI sense: UNIT ATTENTION asc:28,0 (Not ready to ready change, medium may have changed) (da0:umass-sim0:0:0:0): Retrying command (per sense data) g_vfs_done():da0s2[WRITE(offset=799834112, length=131072)]error = 6 /: got error 6 while accessing filesystem /: got error 6 while accessing filesystem /: got error 6 while accessing filesystem /: got error 6 while accessing filesystem g_vfs_done():da0s2[WRITE(offset=799965184, length=131072)]error = 6 /: got error 6 while accessing filesystem /: got error 6 while accessing filesystem /: got error 6 while accessing filesystem /: got error 6 while accessing filesystem g_vfs_done():da0s2[WRITE(offset=800096256, length=131072)]error = 6 /: got error 6 while accessing filesystem /: got error 6 while accessing filesystem /: got error 6 while accessing filesystem /: got error 6 while accessing filesystem g_vfs_done():da0s2[WRITE(offset=800227328, length=131072)]error = 6 /: got error 6 while accessing filesystem /: got error 6 while accessing filesystem /: got error 6 while accessing filesystem /: got error 6 while accessing filesystem softdep_deallocate_dependencies: got error 6 while accessing filesystem g_vfs_done():da0s2[WRITE(offset=800391168, length=131072)]error = 6 g_vfs_done():da0s2[WRITE(offset=800522240, length=131072)]error = 6 g_vfs_done():da0s2[WRITE(offset=800653312, length=131072)]error = 6 g_vfs_done():da0s2[WRITE(offset=800391168, length=131072)]error = 6 /: got error 6 while accessing filesystem /: got error 6 while accessing filesystem /: got error 6 while accessing filesystem /: got error 6 while accessing filesystem g_vfs_done():da0s2[WRITE(offset=800522240, length=131072)]error = 6 /: got error 6 while accessing filesystem /: got error 6 while accessing filesystem /: got error 6 while accessing filesystem /: got error 6 while accessing filesystem g_vfs_done():da0s2[WRITE(offset=800653312, length=131072)]error = 6 /: got error 6 while accessing filesystem /: got error 6 while accessing filesystem /: got error 6 while accessing filesystem /: got error 6 while accessing filesystem g_vfs_done():da0s2[WRITE(offset=800817152, length=131072)]error = 6 /: got error 6 while accessing filesystem /: got error 6 while accessing filesystem /: got error 6 while accessing filesystem /: got error 6 while accessing filesystem g_vfs_done():da0s2[WRITE(offset=800948224, length=131072)]error = 6 /: got error 6 while accessing filesystem /: got error 6 while accessing filesystem /: got error 6 while accessing filesystem /: got error 6 while accessing filesystem g_vfs_done():da0s2[WRITE(offset=801079296, length=131072)]error = 6 /: got error 6 while accessing filesystem /: got error 6 while accessing filesystem /: got error 6 while accessing filesystem /: got error 6 while accessing filesystem g_vfs_done():da0s2[WRITE(offset=801210368, length=131072)]error = 6 /: got error 6 while accessing filesystem /: got error 6 while accessing filesystem /: got error 6 while accessing filesystem /: got error 6 while accessing filesystem g_vfs_done():da0s2[WRITE(offset=801341440, length=131072)]error = 6 /: got error 6 while accessing filesystem /: got error 6 while accessing filesystem /: got error 6 while accessing filesystem /: got error 6 while accessing filesystem g_vfs_done():da0s2[WRITE(offset=801472512, length=131072)]error = 6 /: got error 6 while accessing filesystem /: got error 6 while accessing filesystem /: got error 6 while accessing filesystem /: got error 6 while accessing filesystem g_vfs_done():da0s2[WRITE(offset=801603584, length=131072)]error = 6 /: got error 6 while accessing filesystem /: got error 6 while accessing filesystem /: got error 6 while accessing filesystem /: got error 6 while accessing filesystem g_vfs_done():da0s2[WRITE(offset=801734656, length=131072)]error = 6 /: got error 6 while accessing filesystem /: got error 6 while accessing filesystem /: got error 6 while accessing filesystem /: got error 6 while accessing filesystem g_vfs_done():da0s2[WRITE(offset=801865728, length=131072)]error = 6 /: got error 6 while accessing filesystem /: got error 6 while accessing filesystem /: got error 6 while accessing filesystem /: got error 6 while accessing filesystem g_vfs_done():da0s2[WRITE(offset=801996800, length=131072)]error = 6 /: got error 6 while accessing filesystem /: got error 6 while accessing filesystem /: got error 6 while accessing filesystem /: got error 6 while accessing filesystem g_vfs_done():da0s2[WRITE(offset=802127872, length=131072)]error = 6 /: got error 6 while accessing filesystem /: got error 6 while accessing filesystem /: got error 6 while accessing filesystem /: got error 6 while accessing filesystem softdep_deallocate_dependencies: got error 6 while accessing filesystem g_vfs_done():da0s2[WRITE(offset=802324480, length=131072)]error = 6 g_vfs_done():da0s2[WRITE(offset=802455552, length=131072)]error = 6 g_vfs_done():da0s2[WRITE(offset=802586624, length=131072)]error = 6 g_vfs_done():da0s2[WRITE(offset=802324480, length=131072)]error = 6 /: got error 6 while accessing filesystem /: got error 6 while accessing filesystem /: got error 6 while accessing filesystem /: got error 6 while accessing filesystem g_vfs_done():da0s2[WRITE(offset=802455552, length=131072)]error = 6 /: got error 6 while accessing filesystem /: got error 6 while accessing filesystem /: got error 6 while accessing filesystem /: got error 6 while accessing filesystem g_vfs_done():da0s2[WRITE(offset=802586624, length=131072)]error = 6 /: got error 6 while accessing filesystem /: got error 6 while accessing filesystem /: got error 6 while accessing filesystem /: got error 6 while accessing filesystem g_vfs_done():da0s2[WRITE(offset=802750464, length=131072)]error = 6 /: got error 6 while accessing filesystem /: got error 6 while accessing filesystem /: got error 6 while accessing filesystem /: got error 6 while accessing filesystem g_vfs_done():da0s2[WRITE(offset=802881536, length=131072)]error = 6 /: got error 6 while accessing filesystem /: got error 6 while accessing filesystem /: got error 6 while accessing filesystem /: got error 6 while accessing filesystem g_vfs_done():da0s2[WRITE(offset=803012608, length=131072)]error = 6 /: got error 6 while accessing filesystem /: got error 6 while accessing filesystem /: got error 6 while accessing filesystem /: got error 6 while accessing filesystem g_vfs_done():da0s2[WRITE(offset=803143680, length=131072)]error = 6 /: got error 6 while accessing filesystem /: got error 6 while accessing filesystem /: got error 6 while accessing filesystem /: got error 6 while accessing filesystem g_vfs_done():da0s2[WRITE(offset=803274752, length=131072)]error = 6 /: got error 6 while accessing filesystem /: got error 6 while accessing filesystem /: got error 6 while accessing filesystem /: got error 6 while accessing filesystem g_vfs_done():da0s2[WRITE(offset=803405824, length=131072)]error = 6 /: got error 6 while accessing filesystem /: got error 6 while accessing filesystem /: got error 6 while accessing filesystem /: got error 6 while accessing filesystem g_vfs_done():da0s2[WRITE(offset=803536896, length=131072)]error = 6 /: got error 6 while accessing filesystem /: got error 6 while accessing filesystem /: got error 6 while accessing filesystem /: got error 6 while accessing filesystem g_vfs_done():da0s2[WRITE(offset=803667968, length=131072)]error = 6 /: got error 6 while accessing filesystem /: got error 6 while accessing filesystem /: got error 6 while accessing filesystem /: got error 6 while accessing filesystem g_vfs_done():da0s2[WRITE(offset=803799040, length=131072)]error = 6 /: got error 6 while accessing filesystem /: got error 6 while accessing filesystem /: got error 6 while accessing filesystem /: got error 6 while accessing filesystem g_vfs_done():da0s2[WRITE(offset=803930112, length=131072)]error = 6 /: got error 6 while accessing filesystem /: got error 6 while accessing filesystem /: got error 6 while accessing filesystem /: got error 6 while accessing filesystem g_vfs_done():da0s2[WRITE(offset=804061184, length=131072)]error = 6 /: got error 6 while accessing filesystem /: got error 6 while accessing filesystem /: got error 6 while accessing filesystem /: got error 6 while accessing filesystem softdep_deallocate_dependencies: got error 6 while accessing filesystem /: got error 6 while accessing filesystem /: got error 6 while accessing filesystem /: got error 6 while accessing filesystem /: got error 6 while accessing filesystem /: got error 6 while accessing filesystem /: got error 6 while accessing filesystem /: got error 6 while accessing filesystem /: got error 6 while accessing filesystem /: got error 6 while accessing filesystem /: got error 6 while accessing filesystem /: got error 6 while accessing filesystem /: got error 6 while accessing filesystem softdep_deallocate_dependencies: got error 6 while accessing filesystem panic: Bad link elm 0xc5418700 prev->next != elm KDB: enter: panic [ thread pid 62848 tid 100082 ] Stopped at kdb_enter+0x4c: ldrb r15, [r15, r15, ror r15]! db>