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 Svjfoy-qXs_g for ; Fri, 24 Feb 2012 09:19:04 +0100 (CET) Received: from mx1.redhat.com (mx1.redhat.com [209.132.183.28]) by mail.saout.de (Postfix) with ESMTP for ; Fri, 24 Feb 2012 09:19:03 +0100 (CET) Message-ID: <4F4747F2.7000001@redhat.com> Date: Fri, 24 Feb 2012 09:18:58 +0100 From: Milan Broz MIME-Version: 1.0 References: <20120223222300.GH22456@tracyreed.org> <20120223231042.GB28778@tansi.org> <20120223235949.GK22456@tracyreed.org> In-Reply-To: <20120223235949.GK22456@tracyreed.org> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Subject: Re: [dm-crypt] poor mysqldump performance List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Tracy Reed Cc: dm-crypt@saout.de On 02/24/2012 12:59 AM, Tracy Reed wrote: > On Fri, Feb 24, 2012 at 12:10:43AM +0100, Arno Wagner spake thusly: >> I notice that you are using a really, really old kernel. >> 2.6.18 is from end of 2006 or so. There were some >> performance issues with the dm-layer, they might just >> still be in this old version. RHEL5 uses old dmcrypt code which is stable but has known limitations. The last change in RHEL was backporting suport for XTS mode. Backporting of some performance changes is almost impossible (if it easy I perhaps tried that long time ago). Also please note that this is exactly where RHEL customer requests helps - and there were no such requests. So other things get priority. So if you are using CentOS my advice is simple - try to upgrade to CentOS6 and test it. It should be in some aspect better but still database performance over dmcrypt can have problems. Setting nr_request will not help btw, this is different problem. Milan