From owner-aic7xxx@FreeBSD.ORG Wed Mar 14 14:06:38 2007 Return-Path: X-Original-To: aic7xxx@freebsd.org Delivered-To: aic7xxx@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [69.147.83.52]) by hub.freebsd.org (Postfix) with ESMTP id 9C79716A402 for ; Wed, 14 Mar 2007 14:06:38 +0000 (UTC) (envelope-from gibbs@scsiguy.com) Received: from ns1.scsiguy.com (www.scsiguy.com [70.89.174.89]) by mx1.freebsd.org (Postfix) with ESMTP id 7394513C483 for ; Wed, 14 Mar 2007 14:06:38 +0000 (UTC) (envelope-from gibbs@scsiguy.com) Received: from [10.0.8.59] (63-138-16-130.customer.static.ip.paetec.net [63.138.16.130] (may be forged)) (authenticated bits=0) by ns1.scsiguy.com (8.13.8/8.13.8) with ESMTP id l2EDg74T058274 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-SHA bits=256 verify=NO) for ; Wed, 14 Mar 2007 07:42:08 -0600 (MDT) (envelope-from gibbs@scsiguy.com) Message-ID: <45F7FBA5.4010404@scsiguy.com> Date: Wed, 14 Mar 2007 09:41:57 -0400 From: "Justin T. Gibbs" User-Agent: Thunderbird 1.5.0.10 (Windows/20070221) MIME-Version: 1.0 To: aic7xxx@freebsd.org References: <20070228204034.GA2379@radix50.net> <45E602B3.2020306@paralan.com> <20070228233314.GA7348@radix50.net> <45E77B30.2090505@paralan.com> <20070302220950.GD7331@radix50.net> <45E8C36C.1020407@paralan.com> <20070314121250.GB2553@radix50.net> In-Reply-To: <20070314121250.GB2553@radix50.net> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Subject: Re: Adaptec 2940UW with Fujitsu MAN3184M X-BeenThere: aic7xxx@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: Adaptec Device Drivers in FreeBSD and Linux List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Wed, 14 Mar 2007 14:06:38 -0000 Baurzhan Ismagulov wrote: > > I've done some tests (hdparm -tT, build the Linux kernel with ccache) > and have seen that my SATA 7.2k ST3320620AS outperforms U160 10k > MAN3184M by up to 30%, so I decided not to use it for the rootfs yet. Make sure you run a fair test. Most SCSI drives are shipped from the factory with the write cache set to "write-through". SATA and ATA drives almost always operate in "write-back" mode. Your 29160 BIOS should have an option to set the caching mode on a per-target basis. If you're system is backed up by a UPS or your FS can handle being lied to, write-back is fine. Otherwise it's really not a safe option. -- Justin