From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail.saout.de ([127.0.0.1]) by localhost (mail.saout.de [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id j31oMrT7UzaK for ; Fri, 24 Feb 2012 03:55:15 +0100 (CET) Received: from mail.copilotco.com (mail.copilotco.com [216.105.40.123]) (using TLSv1 with cipher ADH-AES256-SHA (256/256 bits)) (No client certificate requested) by mail.saout.de (Postfix) with ESMTPS for ; Fri, 24 Feb 2012 03:55:13 +0100 (CET) Received: from tracyreed.org (unknown [10.9.8.6]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (No client certificate requested) by mail.copilotco.com (Postfix) with ESMTP id E425364C3E for ; Thu, 23 Feb 2012 18:55:11 -0800 (PST) Date: Thu, 23 Feb 2012 18:55:10 -0800 From: Tracy Reed Message-ID: <20120224025510.GL22456@tracyreed.org> References: <20120223222300.GH22456@tracyreed.org> <20120224012954.GJ17572@agk-dp.fab.redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20120224012954.GJ17572@agk-dp.fab.redhat.com> Subject: Re: [dm-crypt] poor mysqldump performance List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: dm-crypt@saout.de On Fri, Feb 24, 2012 at 01:29:54AM +0000, Alasdair G Kergon spake thusly: > Have you done much tuning, in particular /sys/block//queue/nr_requests ? > > http://www.redbooks.ibm.com/redpapers/pdfs/redp4285.pdf remains a good background > read. Given that a non-dmcrypt mysqldump on the same disks (different logical volume) finishes and 15 minutes and a dmcrypt mysql backup happens in 30 minutes any tuning being done would have to be dmcrypt-specific and affect something in the dmcrypt layer or above, correct? nr_requests only exists for the physical disk device. Just for kicks I just bumped it up to 8192 from the default 1024 and ran my test again. Same performance: Twice as slow as without dmcrypt. -- Tracy Reed