From owner-freebsd-performance@FreeBSD.ORG Mon Nov 1 11:33:13 2004 Return-Path: Delivered-To: freebsd-performance@freebsd.org Received: from mx1.FreeBSD.org (mx1.freebsd.org [216.136.204.125]) by hub.freebsd.org (Postfix) with ESMTP id 70EE416A4CE for ; Mon, 1 Nov 2004 11:33:13 +0000 (GMT) Received: from web41204.mail.yahoo.com (web41204.mail.yahoo.com [66.218.93.37]) by mx1.FreeBSD.org (Postfix) with SMTP id 3E80443D54 for ; Mon, 1 Nov 2004 11:33:13 +0000 (GMT) (envelope-from arne_woerner@yahoo.com) Message-ID: <20041101113313.25399.qmail@web41204.mail.yahoo.com> Received: from [83.129.177.150] by web41204.mail.yahoo.com via HTTP; Mon, 01 Nov 2004 03:33:13 PST Date: Mon, 1 Nov 2004 03:33:13 -0800 (PST) From: Arne "Wörner" To: freebsd-performance@freebsd.org MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Subject: hw.ata.wc=0 X-BeenThere: freebsd-performance@freebsd.org X-Mailman-Version: 2.1.1 Precedence: list List-Id: Performance/tuning List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Mon, 01 Nov 2004 11:33:13 -0000 I observed some inconsistencies after I set hw.ata.wc to zero (0): 1. atacontrol does not confirm that write caching is disabled. 2. The write speed on a freshly boot system increases by a factor of 5-6 after a long read. I would like to know, if somebody here has experiences with turning off the write cache of ata devices (how to turn off / how much is performance effected by the hard disc write cache). Thank you. I already posted this to freebsd-fs@freebsd.org but they did not know so much about this matter. -Arne __________________________________ Do you Yahoo!? Yahoo! Mail - You care about security. So do we. http://promotions.yahoo.com/new_mail