From owner-freebsd-fs@FreeBSD.ORG Wed Aug 31 07:44:17 2011 Return-Path: Delivered-To: freebsd-fs@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:4f8:fff6::34]) by hub.freebsd.org (Postfix) with ESMTP id 4724B106566B for ; Wed, 31 Aug 2011 07:44:17 +0000 (UTC) (envelope-from daniel@digsys.bg) Received: from smtp-sofia.digsys.bg (smtp-sofia.digsys.bg [193.68.3.230]) by mx1.freebsd.org (Postfix) with ESMTP id A94418FC0C for ; Wed, 31 Aug 2011 07:44:16 +0000 (UTC) Received: from dcave.digsys.bg (dcave.digsys.bg [192.92.129.5]) (authenticated bits=0) by smtp-sofia.digsys.bg (8.14.4/8.14.4) with ESMTP id p7V7AVnr066398 (version=TLSv1/SSLv3 cipher=DHE-RSA-CAMELLIA256-SHA bits=256 verify=NO) for ; Wed, 31 Aug 2011 10:10:36 +0300 (EEST) (envelope-from daniel@digsys.bg) Message-ID: <4E5DDE66.5000508@digsys.bg> Date: Wed, 31 Aug 2011 10:10:30 +0300 From: Daniel Kalchev User-Agent: Mozilla/5.0 (X11; FreeBSD amd64; rv:6.0) Gecko/20110822 Thunderbird/6.0 MIME-Version: 1.0 To: freebsd-fs@freebsd.org References: <1945418039.20110830231024@serebryakov.spb.ru> <317753422.20110830231815@serebryakov.spb.ru> <20110831004251.GA89979@icarus.home.lan> In-Reply-To: <20110831004251.GA89979@icarus.home.lan> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Subject: Re: Very inconsistent (read) speed on UFS2 X-BeenThere: freebsd-fs@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: Filesystems List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Wed, 31 Aug 2011 07:44:17 -0000 On 31.08.11 03:42, Jeremy Chadwick wrote: > There is a possibility that one of your drives could be performing at > less-than-ideal rates (yes, intermittently) and therefore impacts > (intermittently) your overall I/O throughput. This is very probable, given RAID5, that needs to read stripes off every disc on every read. Probably some S.M.A.R.T. investigation might help (different measurements for different drives, if supported by the drives, that is). Daniel