From owner-freebsd-questions@FreeBSD.ORG Thu Feb 21 10:41:44 2008 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 84EAE16A400 for ; Thu, 21 Feb 2008 10:41:44 +0000 (UTC) (envelope-from cpghost@cordula.ws) Received: from fw.farid-hajji.net (fw.farid-hajji.net [213.146.115.42]) by mx1.freebsd.org (Postfix) with ESMTP id 2862313C44B for ; Thu, 21 Feb 2008 10:41:44 +0000 (UTC) (envelope-from cpghost@cordula.ws) Received: from epia-2.farid-hajji.net (epia-2 [192.168.254.11]) by fw.farid-hajji.net (Postfix) with ESMTP id 4F3D4DB487; Thu, 21 Feb 2008 11:41:42 +0100 (CET) Date: Thu, 21 Feb 2008 03:41:41 -0700 From: cpghost To: "s.g." Message-ID: <20080221104141.GA80437@epia-2.farid-hajji.net> References: <47BA962E.5060504@theconcept.ru> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <47BA962E.5060504@theconcept.ru> User-Agent: Mutt/1.5.17 (2007-11-01) Cc: freebsd-questions@freebsd.org Subject: Re: GELI encryption and HDD critical temperature 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: Thu, 21 Feb 2008 10:41:44 -0000 On Tue, Feb 19, 2008 at 11:41:18AM +0300, s.g. wrote: > According to smartctl -a, the temperature of the encrypted drives is ~59C. > The temperature of the unencrypted drive is, however, ~41C, according to > the same smartctl -a. The CPU has to work extra hard to encrypt/decrypt, and it is possible that the extra heat this generates is absorbed by the HDDs. But since the only drive that's overheating is the encrypted one, it seems to be something else. > Am I right assuming GELI encryption is the reason for such a "global > warming"? I don't know. But I've noticed that when drives access GBDE-encrypted partitions (I didn't try with GELI yet), they are much louder (head seeking). It seems they seek more often on encrypted than non-encrypted partitions. Perhaps caching is turned off at some point up the chain? If that's the case, it is no wonder that encrypted partitions tend to result in higher drive temps (and faster drive wear). Is there a way to measure the number of head seeks in near real-time to confirm or disprove this? > Grigorian -cpghost. -- Cordula's Web. http://www.cordula.ws/