From owner-freebsd-geom@FreeBSD.ORG Sun Apr 30 15:53:28 2006 Return-Path: X-Original-To: freebsd-geom@FreeBSD.org Delivered-To: freebsd-geom@FreeBSD.org Received: from mx1.FreeBSD.org (mx1.freebsd.org [216.136.204.125]) by hub.freebsd.org (Postfix) with ESMTP id 2FFAC16A423; Sun, 30 Apr 2006 15:53:28 +0000 (UTC) (envelope-from fernan@iib.unsam.edu.ar) Received: from smtp.unsam.edu.ar (smtp.unsam.edu.ar [170.210.48.3]) by mx1.FreeBSD.org (Postfix) with ESMTP id 1C1E843D79; Sun, 30 Apr 2006 15:53:14 +0000 (GMT) (envelope-from fernan@iib.unsam.edu.ar) Received: from omega.iib.unsam.edu.ar (omega.iib.unsam.edu.ar [192.168.10.14]) by smtp.unsam.edu.ar (8.12.6/8.12.6) with ESMTP id k3UFtG3u069674; Sun, 30 Apr 2006 12:55:16 -0300 (ART) (envelope-from fernan@iib.unsam.edu.ar) Received: from omega.iib.unsam.edu.ar (localhost [127.0.0.1]) by omega.iib.unsam.edu.ar (8.13.4/8.13.4) with ESMTP id k3UFqrCA078947; Sun, 30 Apr 2006 12:52:53 -0300 (ART) (envelope-from fernan@iib.unsam.edu.ar) Received: (from fernan@localhost) by omega.iib.unsam.edu.ar (8.13.4/8.13.3/Submit) id k3UFqr10078946; Sun, 30 Apr 2006 12:52:53 -0300 (ART) (envelope-from fernan@iib.unsam.edu.ar) X-Authentication-Warning: omega.iib.unsam.edu.ar: fernan set sender to fernan@iib.unsam.edu.ar using -f Date: Sun, 30 Apr 2006 12:52:53 -0300 From: Fernan Aguero To: Pawel Jakub Dawidek Message-ID: <20060430155253.GB71384@iib.unsam.edu.ar> References: <20060428171226.GG62606@iib.unsam.edu.ar> <20060429145525.GJ4896@garage.freebsd.pl> <20060429211907.GA2855@iib.unsam.edu.ar> <20060429213842.GM4896@garage.freebsd.pl> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20060429213842.GM4896@garage.freebsd.pl> User-Agent: Mutt/1.5.11 Cc: freebsd-geom@FreeBSD.org Subject: Re: panic when loading mirror X-BeenThere: freebsd-geom@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: GEOM-specific discussions and implementations List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Sun, 30 Apr 2006 15:53:28 -0000 +----[ Pawel Jakub Dawidek (29.Apr.2006 18:44): | | On Sat, Apr 29, 2006 at 06:19:07PM -0300, Fernan Aguero wrote: | +> +----[ Pawel Jakub Dawidek (29.Apr.2006 12:02): | +> | You should configure both slices and partitions on mirrored provider. | +> | +> Pawel, | +> | +> thanks for your reply. | +> | +> If you say that I should set up the mirror first and then | +> slice and partition, I cannot but trust. But this is not | +> what I see here: http://people.freebsd.org/~rse/mirror/ | +> | +> # place a GEOM mirror label onto first slice of second disk | +> # (actually on the last block of the disk slice) | +> gmirror label -v -n -b round-robin gm0s1 /dev/ad1s1 | +> | +> the provider is already a slice, only partitions are done after | +> configuring and loading the mirror ... | +> | +> I'll try what you suggest, but I'll have to reintall the | +> whole box to do that. | | Sorry, you have to have slices when you configure mirror on top of them. | Everything below (in your case partitions) you should configure on a | mirror device. OK, thanks for the clarification. | +> | To fix it you need to clear the old metadata first. | +> | +> I'm not following you here ... what metadata? The one added | +> by 'gmirror label'? Or metadata added by the normal | +> fdisk/disklabel process that I do when first installing the | +> box? | | The latter. You can do it with gmirror turned off with this command: | | # dd if=/dev/zero of=/dev/ad0s1 count=16 | | This will destroy all your partitions. got it now. I'll try that next tuesday when I get back to the lab. However, just for the record, these slices never had any partitions ... I just created them when installing the box, but didn't do anything with them till now (all the partitions were created in the 's2' slices). | +> | +> Or is this something that is expected to happen and should | +> | +> be fixed? | +> | | +> | This shouldn't act that way and panic your box for sure... | +> | +> That's what I thought. Should I file a PR? Under which | +> category? | | Your report is not the first one related to the problem, so I wouldn't | be surprised if there is already PR describing it. I couldn't fint it ... but I was looking at open PRs only ... maybe it was already committed to -CURRENT and closed? I'll keep looking ... Fernan | -- | Pawel Jakub Dawidek http://www.wheel.pl | pjd@FreeBSD.org http://www.FreeBSD.org | FreeBSD committer Am I Evil? Yes, I Am! | +----] From owner-freebsd-geom@FreeBSD.ORG Sun Apr 30 15:57:07 2006 Return-Path: X-Original-To: freebsd-geom@FreeBSD.org Delivered-To: freebsd-geom@FreeBSD.org Received: from mx1.FreeBSD.org (mx1.freebsd.org [216.136.204.125]) by hub.freebsd.org (Postfix) with ESMTP id 8E0FE16A400 for ; Sun, 30 Apr 2006 15:57:07 +0000 (UTC) (envelope-from pjd@garage.freebsd.pl) Received: from mail.garage.freebsd.pl (arm132.internetdsl.tpnet.pl [83.17.198.132]) by mx1.FreeBSD.org (Postfix) with ESMTP id E80CA43D45 for ; Sun, 30 Apr 2006 15:57:06 +0000 (GMT) (envelope-from pjd@garage.freebsd.pl) Received: by mail.garage.freebsd.pl (Postfix, from userid 65534) id 4560352C73; Sun, 30 Apr 2006 17:57:04 +0200 (CEST) Received: from localhost (dkf188.neoplus.adsl.tpnet.pl [83.24.9.188]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (No client certificate requested) by mail.garage.freebsd.pl (Postfix) with ESMTP id 62E1E50F93; Sun, 30 Apr 2006 17:56:59 +0200 (CEST) Date: Sun, 30 Apr 2006 17:55:13 +0200 From: Pawel Jakub Dawidek To: Fernan Aguero Message-ID: <20060430155513.GB10174@garage.freebsd.pl> References: <20060428171226.GG62606@iib.unsam.edu.ar> <20060429145525.GJ4896@garage.freebsd.pl> <20060429211907.GA2855@iib.unsam.edu.ar> <20060429213842.GM4896@garage.freebsd.pl> <20060430155253.GB71384@iib.unsam.edu.ar> Mime-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha1; protocol="application/pgp-signature"; boundary="neYutvxvOLaeuPCA" Content-Disposition: inline In-Reply-To: <20060430155253.GB71384@iib.unsam.edu.ar> X-PGP-Key-URL: http://people.freebsd.org/~pjd/pjd.asc X-OS: FreeBSD 7.0-CURRENT i386 User-Agent: mutt-ng/devel-r535 (FreeBSD) X-Spam-Checker-Version: SpamAssassin 3.0.4 (2005-06-05) on mail.garage.freebsd.pl X-Spam-Level: X-Spam-Status: No, score=-0.5 required=3.0 tests=BAYES_00,RCVD_IN_NJABL_DUL, RCVD_IN_SORBS_DUL autolearn=no version=3.0.4 Cc: freebsd-geom@FreeBSD.org Subject: Re: panic when loading mirror X-BeenThere: freebsd-geom@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: GEOM-specific discussions and implementations List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Sun, 30 Apr 2006 15:57:07 -0000 --neYutvxvOLaeuPCA Content-Type: text/plain; charset=iso-8859-2 Content-Disposition: inline Content-Transfer-Encoding: quoted-printable On Sun, Apr 30, 2006 at 12:52:53PM -0300, Fernan Aguero wrote: +> | +> That's what I thought. Should I file a PR? Under which +> | +> category?=20 +> |=20 +> | Your report is not the first one related to the problem, so I wouldn't +> | be surprised if there is already PR describing it. +>=20 +> I couldn't fint it ... but I was looking at open PRs only +> ... maybe it was already committed to -CURRENT and closed? +>=20 +> I'll keep looking ... I'm not sure there is PR already, but it was reported for sure. If you won't find one, please file one. --=20 Pawel Jakub Dawidek http://www.wheel.pl pjd@FreeBSD.org http://www.FreeBSD.org FreeBSD committer Am I Evil? Yes, I Am! --neYutvxvOLaeuPCA Content-Type: application/pgp-signature Content-Disposition: inline -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.2 (FreeBSD) iD8DBQFEVN3hForvXbEpPzQRAouWAKDFpabZO0dfbrGdf4e/+Qa785oVpwCgx18X BrjeW8oy/6KOkVoi36igDTk= =IZkm -----END PGP SIGNATURE----- --neYutvxvOLaeuPCA-- From owner-freebsd-geom@FreeBSD.ORG Mon May 1 11:02:30 2006 Return-Path: X-Original-To: freebsd-geom@freebsd.org Delivered-To: freebsd-geom@freebsd.org Received: from mx1.FreeBSD.org (mx1.freebsd.org [216.136.204.125]) by hub.freebsd.org (Postfix) with ESMTP id 0C6B816A400 for ; Mon, 1 May 2006 11:02:30 +0000 (UTC) (envelope-from owner-bugmaster@freebsd.org) Received: from freefall.freebsd.org (freefall.freebsd.org [216.136.204.21]) by mx1.FreeBSD.org (Postfix) with ESMTP id B8AD143D48 for ; Mon, 1 May 2006 11:02:29 +0000 (GMT) (envelope-from owner-bugmaster@freebsd.org) Received: from freefall.freebsd.org (peter@localhost [127.0.0.1]) by freefall.freebsd.org (8.13.4/8.13.4) with ESMTP id k41B2TeQ008964 for ; Mon, 1 May 2006 11:02:29 GMT (envelope-from owner-bugmaster@freebsd.org) Received: (from peter@localhost) by freefall.freebsd.org (8.13.4/8.13.4/Submit) id k41B2RoW008958 for freebsd-geom@freebsd.org; Mon, 1 May 2006 11:02:27 GMT (envelope-from owner-bugmaster@freebsd.org) Date: Mon, 1 May 2006 11:02:27 GMT Message-Id: <200605011102.k41B2RoW008958@freefall.freebsd.org> X-Authentication-Warning: freefall.freebsd.org: peter set sender to owner-bugmaster@freebsd.org using -f From: FreeBSD bugmaster To: freebsd-geom@FreeBSD.org Cc: Subject: Current problem reports assigned to you X-BeenThere: freebsd-geom@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: GEOM-specific discussions and implementations List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Mon, 01 May 2006 11:02:30 -0000 Current FreeBSD problem reports Critical problems Serious problems S Submitted Tracker Resp. Description ------------------------------------------------------------------------------- o [2005/01/21] kern/76538 geom [gbde] nfs-write on gbde partition stalls o [2005/08/04] kern/84556 geom [geom] GBDE-encrypted swap causes panic a o [2005/10/16] kern/87544 geom [gbde] mmaping large files on a gbde file o [2005/11/16] kern/89102 geom [geom_vfs] [panic] panic when forced unmo o [2005/12/08] bin/90093 geom fdisk(8) incapable of altering in-core ge o [2005/12/18] kern/90582 geom [geom_mirror] [panic] Restore cause panic o [2006/04/15] kern/95771 geom [geom] geom mirror provider destroyed (ma 7 problems total. Non-critical problems S Submitted Tracker Resp. Description ------------------------------------------------------------------------------- o [2005/02/26] bin/78131 geom gbde "destroy" not working. o [2005/03/26] kern/79251 geom [2TB] newfs fails on 2.6TB gbde device o [2006/03/18] kern/94632 geom [geom] Kernel output resets input while G 3 problems total. From owner-freebsd-geom@FreeBSD.ORG Mon May 1 14:46:17 2006 Return-Path: X-Original-To: freebsd-geom@freebsd.org Delivered-To: freebsd-geom@freebsd.org Received: from mx1.FreeBSD.org (mx1.freebsd.org [216.136.204.125]) by hub.freebsd.org (Postfix) with ESMTP id 5CFCC16A40B for ; Mon, 1 May 2006 14:46:17 +0000 (UTC) (envelope-from aswood@gmail.com) Received: from nz-out-0102.google.com (nz-out-0102.google.com [64.233.162.197]) by mx1.FreeBSD.org (Postfix) with ESMTP id B5E3343D46 for ; Mon, 1 May 2006 14:46:16 +0000 (GMT) (envelope-from aswood@gmail.com) Received: by nz-out-0102.google.com with SMTP id x3so2868303nzd for ; Mon, 01 May 2006 07:46:16 -0700 (PDT) DomainKey-Signature: a=rsa-sha1; q=dns; c=nofws; s=beta; d=gmail.com; h=received:message-id:date:from:to:subject:in-reply-to:mime-version:content-type:content-transfer-encoding:content-disposition:references; b=armLyX45gk/REb4rkxPLD/mTlf36nkHizsYiqVlcvGXb0aIHKgwZ2qlNa7XZrYcKRpEz6LnNv8DiGFbPyqlhY1o2AaM5RhrA5OPFKO6H/BVRDsVIiR/PG6D6qTtDuo2QbBYmNpDFrcdkz7vR0lA8k/EScjIsfMiOEBwFosLifGs= Received: by 10.36.132.19 with SMTP id f19mr763283nzd; Mon, 01 May 2006 07:46:16 -0700 (PDT) Received: by 10.36.138.11 with HTTP; Mon, 1 May 2006 07:46:16 -0700 (PDT) Message-ID: <77518d100605010746v4870bf6bi2e3ca63ff8a1a002@mail.gmail.com> Date: Mon, 1 May 2006 09:46:16 -0500 From: "Adam Wood" To: "Frank J. Beckmann" , freebsd-geom@freebsd.org In-Reply-To: <200604201312.22878.frank@barda.agala.net> MIME-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: quoted-printable Content-Disposition: inline References: <200604201312.22878.frank@barda.agala.net> Cc: Subject: Re: How to make a bootable USB stick for booting a geli encryptethard disk? X-BeenThere: freebsd-geom@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: GEOM-specific discussions and implementations List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Mon, 01 May 2006 14:46:17 -0000 Hello, On 4/20/06, Frank J. Beckmann wrote: > Yes, but there are many kind people here who explain waht to do. Seems you're right; try this: http://typo.submonkey.net/articles/2006/04/13/installing-freebsd-on-usb-sti= ck-episode-2 From owner-freebsd-geom@FreeBSD.ORG Mon May 1 19:14:45 2006 Return-Path: X-Original-To: freebsd-geom@FreeBSD.org Delivered-To: freebsd-geom@FreeBSD.org Received: from mx1.FreeBSD.org (mx1.freebsd.org [216.136.204.125]) by hub.freebsd.org (Postfix) with ESMTP id B37E316A415 for ; Mon, 1 May 2006 19:14:45 +0000 (UTC) (envelope-from kgunders@teamcool.net) Received: from koyukuk.teamcool.net (koyukuk.teamcool.net [209.161.34.19]) by mx1.FreeBSD.org (Postfix) with ESMTP id 4D05943D5A for ; Mon, 1 May 2006 19:14:45 +0000 (GMT) (envelope-from kgunders@teamcool.net) Received: from koyukuk.teamcool.net (localhost [127.0.0.1]) by koyukuk.teamcool.net (TeamCool Rocks) with ESMTP id A1D92F828 for ; Mon, 1 May 2006 13:14:44 -0600 (MDT) Received: from cochise.teamcool.net (unknown [192.168.1.57]) by koyukuk.teamcool.net (TeamCool Rocks) with ESMTP id 56822F812 for ; Mon, 1 May 2006 13:14:44 -0600 (MDT) Date: Mon, 1 May 2006 13:14:43 -0600 From: Ken Gunderson To: freebsd-geom@FreeBSD.org Message-Id: <20060501131443.0997e120.kgunders@teamcool.net> Organization: Teamcool Networks X-Mailer: Sylpheed version 1.9.12 (GTK+ 2.6.7; i386-portbld-freebsd5.4) Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit X-Virus-Scanned: ClamAV using ClamSMTP Cc: Subject: nvidia onboard vs. gmirror perfomance X-BeenThere: freebsd-geom@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: GEOM-specific discussions and implementations List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Mon, 01 May 2006 19:14:45 -0000 Howdy Folks: I've been using gmirror for quite some while now and it's worked well for me. However, I was wondering how it performed in comparison to nVidia onboard raid offerings on various nforce boards that FreeBSD now supports. For example, the fbsd-adm64 mainboard support page links to this dmesg for a Sun X2100: The part relevant to the task at hand being: "The onboard raid is fully functional to me (WD Raptors instead of the stock seagate disks). I made a bonnie test which showed imressive perfomance, but slightly hight CPU usage." Is anyone aware of any benchmarks comparing the nvidia raid1 to gmirror? -- Best regards, Ken Gunderson Q: Because it reverses the logical flow of conversation. A: Why is putting a reply at the top of the message frowned upon? From owner-freebsd-geom@FreeBSD.ORG Wed May 3 22:28:43 2006 Return-Path: X-Original-To: freebsd-geom@freebsd.org Delivered-To: freebsd-geom@freebsd.org Received: from mx1.FreeBSD.org (mx1.freebsd.org [216.136.204.125]) by hub.freebsd.org (Postfix) with ESMTP id BA32016A400; Wed, 3 May 2006 22:28:43 +0000 (UTC) (envelope-from kgunders@teamcool.net) Received: from koyukuk.teamcool.net (koyukuk.teamcool.net [209.161.34.19]) by mx1.FreeBSD.org (Postfix) with ESMTP id 50E5543D45; Wed, 3 May 2006 22:28:42 +0000 (GMT) (envelope-from kgunders@teamcool.net) Received: from koyukuk.teamcool.net (localhost [127.0.0.1]) by koyukuk.teamcool.net (TeamCool Rocks) with ESMTP id E8CA5F812; Wed, 3 May 2006 16:28:41 -0600 (MDT) Received: from cochise.teamcool.net (unknown [192.168.1.57]) by koyukuk.teamcool.net (TeamCool Rocks) with ESMTP id 9E1D5F7BB; Wed, 3 May 2006 16:28:41 -0600 (MDT) Date: Wed, 3 May 2006 16:28:40 -0600 From: Ken Gunderson To: Mike Jakubik Message-Id: <20060503162840.76202daa.kgunders@teamcool.net> In-Reply-To: <1146646812.57259.2.camel@desktop.home.local> References: <20060503021432.2bd96c7e.kgunders@teamcool.net> <1146646812.57259.2.camel@desktop.home.local> Organization: Teamcool Networks X-Mailer: Sylpheed version 1.9.12 (GTK+ 2.6.7; i386-portbld-freebsd5.4) Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit X-Virus-Scanned: ClamAV using ClamSMTP Cc: freebsd-amd64@FreeBSD.org, freebsd-geom@freebsd.org Subject: Re: performance of nvidia onboard raid1 vs. gmirror X-BeenThere: freebsd-geom@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: GEOM-specific discussions and implementations List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Wed, 03 May 2006 22:28:43 -0000 On Wed, 03 May 2006 05:00:12 -0400 Mike Jakubik wrote: > On Wed, 2006-05-03 at 02:14 -0600, Ken Gunderson wrote: > > Is anyone aware of any benchmarks comparing the nvidia raid1 to > > gmirror? Or have any additional insights? I don't have a machine free > > I can test on at the moment but might in next week or two if anyone else > > is interested. > > I am sure many people are interested in such a benchmark, but no one has > done it yet. If you have the resources to do so, please go ahead and > continue. Many of us would be interested in your results. Sorry to follow up on this twice but I have subsequently heard back from Andras. Also cross posting to fbsd-geom in case anyone there might be interested... 1) Here's Andras's bonnie benchmarks w/nvidia onboard: [13:39:05]:root@x2100:/data#/usr/local/bin/bonnie File './Bonnie.55923', size: 104857600 Writing with putc()...done Rewriting...done Writing intelligently...done Reading with getc()...done Reading intelligently...done Seeker 1...Seeker 2...Seeker 3...start 'em...done...done...done... -------Sequential Output-------- ---Sequential Input-- --Random-- -Per Char- --Block--- -Rewrite-- -Per Char- --Block--- --Seeks--- Machine MB K/sec %CPU K/sec %CPU K/sec %CPU K/sec %CPU K/sec %CPU /sec %CPU 100 47243 42.5 58564 17.4 58202 21.7 96759 99.9 573917 100.0 52176.4 138.3 [13:39:22]:root@x2100:/data#/usr/local/bin/bonnie -s 1000 File './Bonnie.55932', size: 1048576000 Writing with putc()...done Rewriting...done Writing intelligently...done Reading with getc()...done Reading intelligently...done Seeker 1...Seeker 2...Seeker 3...start 'em...done...done...done... -------Sequential Output-------- ---Sequential Input-- --Random-- -Per Char- --Block--- -Rewrite-- -Per Char- --Block--- --Seeks--- Machine MB K/sec %CPU K/sec %CPU K/sec %CPU K/sec %CPU K/sec %CPU /sec %CPU 1000 42357 38.5 50102 15.8 48224 18.3 87487 100.0 576442 100.0 27145.9 121.7 These test were done with RELENG_6_1 (apr 29 version iirc). 2) Here's mine with gmirror. FreeBSD 6.0-RELEASE-p7 w/amd64 bits: selway# bonnie -m selway File './Bonnie.7135', size: 104857600 Writing with putc()...done Rewriting...done Writing intelligently...done Reading with getc()...done Reading intelligently...done Seeker 1...Seeker 2...Seeker 3...start 'em...done...done...done... -------Sequential Output-------- ---Sequential Input-- --Random-- -Per Char- --Block--- -Rewrite-- -Per Char- --Block--- --Seeks--- Machine MB K/sec %CPU K/sec %CPU K/sec %CPU K/sec %CPU K/sec %CPU /sec %CPU selway 100 68523 56.8 50932 11.3 88951 19.4 93775 99.9 1482446 99.9 79856.3 155.0 selway# bonnie -m selway -s 1000 File './Bonnie.7139', size: 1048576000 Writing with putc()...done Rewriting...done Writing intelligently...done Reading with getc()...done Reading intelligently...done Seeker 1...Seeker 2...Seeker 3...start 'em...done...done...done... -------Sequential Output-------- ---Sequential Input-- --Random-- -Per Char- --Block--- -Rewrite-- -Per Char- --Block--- --Seeks--- Machine MB K/sec %CPU K/sec %CPU K/sec %CPU K/sec %CPU K/sec %CPU /sec %CPU selway 1000 67419 57.7 64774 15.4 62163 18.3 95277 99.9 904320 99.9 28088.5 127.2 Not exactly apples to apples but you get basic idea. The machines both use same mainboard and HD's. Mine is running Opteron165 CPU, don't know about the other. gmirror is looking pretty good:) -- Best regards, Ken Gunderson Q: Because it reverses the logical flow of conversation. A: Why is putting a reply at the top of the message frowned upon?