From owner-freebsd-questions@FreeBSD.ORG Wed Feb 4 17:29:32 2009 Return-Path: Delivered-To: freebsd-questions@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:4f8:fff6::34]) by hub.freebsd.org (Postfix) with ESMTP id 6DE2910656EF for ; Wed, 4 Feb 2009 17:29:32 +0000 (UTC) (envelope-from hugo@barafranca.com) Received: from mail.barafranca.com (mail.barafranca.com [67.213.67.47]) by mx1.freebsd.org (Postfix) with ESMTP id 3D3CF8FC1B for ; Wed, 4 Feb 2009 17:29:32 +0000 (UTC) (envelope-from hugo@barafranca.com) Received: from localhost (unknown [172.16.100.24]) by mail.barafranca.com (Postfix) with ESMTP id 091518E6 for ; Wed, 4 Feb 2009 17:04:43 +0000 (UTC) X-Virus-Scanned: amavisd-new at barafranca.com Received: from mail.barafranca.com ([172.16.100.24]) by localhost (mail.barafranca.com [172.16.100.24]) (amavisd-new, port 10024) with ESMTP id j0f3VF7O1ULG for ; Wed, 4 Feb 2009 17:04:14 +0000 (UTC) Received: from [10.0.30.27] (adslfixo-b3-115-114.telepac.pt [213.13.115.114]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (No client certificate requested) by mail.barafranca.com (Postfix) with ESMTPSA id C8D708DB for ; Wed, 4 Feb 2009 17:04:13 +0000 (UTC) Message-ID: <4989D8B6.80505@barafranca.com> Date: Wed, 04 Feb 2009 18:04:38 +0000 From: Hugo Silva User-Agent: Thunderbird 2.0.0.9 (X11/20071213) MIME-Version: 1.0 To: freebsd-questions@freebsd.org Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Subject: GEOM_JOURNAL on a 550G partition - opinions ? X-BeenThere: freebsd-questions@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: User questions List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Wed, 04 Feb 2009 17:29:34 -0000 Hi list, For a server I will be setting up, I am considering using gjournal on the partition that will hold all the www data. The journaled partition (mounted async) would be mostly read from, uploads would not be very frequent and most sites wouldn't write to the disk. Logs would be kept elsewhere. This server will have two hard disks, mirrored (gmirror) at the disk level. Here are my questions: - Will the fact that gmirror is underneath the journal (/dev/mirror/gm0s1f.journal) affect performance ? (either positively or negatively) (* I would be keeping the journal in the same provider) - Would reads / writes be faster? considerably faster ? (gjournal) I've seen different numbers from different places, the impression I got is that reads should be faster while writes will be substantially slower - is this correct ? - What about reliability ? From the manpage, I know that if I journaled the entire mirror, I would not need to sync it after an unclean shutdown. Going from the assumption that this will not be so for a single journaled partition, will there be any interference between gjournal and gmirror ? - I've never had an UFS2 partition filled with more than 200G of data, so I am not sure what to expect for 550G with soft-updates (I expect this partition to hold close to 550G of data) - real numbers about this would also be helpful. Any personal experiences concerning gjournal or gmirror+gjournal are greatly appreciated! Thanks. Hugo