From owner-freebsd-stable@FreeBSD.ORG Sun Feb 3 21:45:55 2008 Return-Path: Delivered-To: freebsd-stable@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:4f8:fff6::34]) by hub.freebsd.org (Postfix) with ESMTP id 9A09616A419 for ; Sun, 3 Feb 2008 21:45:55 +0000 (UTC) (envelope-from imb@protected-networks.net) Received: from sarah.protected-networks.net (sarah.protected-networks.net [64.46.156.146]) by mx1.freebsd.org (Postfix) with ESMTP id 4D07213C46B for ; Sun, 3 Feb 2008 21:45:55 +0000 (UTC) (envelope-from imb@protected-networks.net) Received: from toshi.auburn.protected-networks.net (toshi.auburn.protected-networks.net [202.12.127.84]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (Client CN "Iain Michael Butler", Issuer "Protected Networks Certificate Authority" (verified OK)) (Authenticated sender: imb) by sarah.protected-networks.net (Postfix) with ESMTP id B15476107; Sun, 3 Feb 2008 16:45:53 -0500 (EST) DKIM-Signature: v=1; a=rsa-sha256; c=simple/simple; d=protected-networks.net; s=200705; t=1202075154; bh=GxNssaZauT1gfg fsff681XymDxHrW150NeFC3vEPpvo=; h=DomainKey-Signature:Message-ID: Date:From:User-Agent:MIME-Version:To:CC:Subject:References: In-Reply-To:X-Enigmail-Version:OpenPGP:Content-Type: Content-Transfer-Encoding; b=S5PtxOxwZ4P8WRk+cNVlFteoCsEymwECv1YSv Jtii3QJtqa6jCAfxXrcGvphhL6u+5ZBJX3sKqgzyRHsaKZi7VkRXT1agew/seJPeqgv CtjZb6ygUVKLhxYtlv7Pawgw DomainKey-Signature: a=rsa-sha1; s=200509; d=protected-networks.net; c=nofws; q=dns; h=message-id:date:from:user-agent:mime-version:to:cc:subject: references:in-reply-to:x-enigmail-version:openpgp:content-type:content-transfer-encoding; b=F7zU29QA7YEiKGinZEILQstugb3GUjbF8JI4j8XabpuMpGW80p1OwcHDYiE/bEXO/ 1OrlNDR2y+nBgRAtOihfz0ArAbTw5bUfJ16PzetlGMbqejTh9HRk2lzel83gKXB Message-ID: <47A63610.4070608@protected-networks.net> Date: Sun, 03 Feb 2008 16:45:52 -0500 From: Michael Butler User-Agent: Thunderbird 2.0.0.9 (X11/20080124) MIME-Version: 1.0 To: Chris References: <3aaaa3a0802030751w69ce59a9oeb869e3d87d92616@mail.gmail.com> <47A62B00.1060403@egr.msu.edu> <3aaaa3a0802031318y2e3fd33en8071c82172ab9ecf@mail.gmail.com> In-Reply-To: <3aaaa3a0802031318y2e3fd33en8071c82172ab9ecf@mail.gmail.com> X-Enigmail-Version: 0.95.6 OpenPGP: id=0442D492 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Cc: Adam McDougall , freebsd-stable@freebsd.org, Ivan Voras Subject: Re: gjournal panic 7.0-RC1 X-BeenThere: freebsd-stable@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: Production branch of FreeBSD source code List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Sun, 03 Feb 2008 21:45:55 -0000 Chris wrote: > If the only advantage of journaling is to avoid slow fsck's then I may > decide I can live without it, the real attraction to me was been able > to use the much glamorised async which is what made me so shocked when > write speeds were low. If I understood this thread correctly, the impression of poor performance is based on a configuration where both the journal and the data are on the same physical drive. Intuitively, this will likely penalize any transaction on the volume, read or write, since you're asking the drive to not only accumulate a queue of information to the journal in one region of the disk but also to flush that data in "idle time" to a region in the data space on that same disk at a significant seek-length away. I would think that journaling on one drive and storing the resultant data-set on another would improve performance enormously (reduced seek-lengths) and more so if they were 1) high-rpm drives (less rotational latency) and 2) on different buses (no bus/controller contention), Michael