From owner-freebsd-hackers@FreeBSD.ORG Fri Jan 18 20:29:10 2013 Return-Path: Delivered-To: freebsd-hackers@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:1900:2254:206a::19:1]) by hub.freebsd.org (Postfix) with ESMTP id 01B7270 for ; Fri, 18 Jan 2013 20:29:10 +0000 (UTC) (envelope-from scott4long@yahoo.com) Received: from nm24-vm7.bullet.mail.gq1.yahoo.com (nm24-vm7.bullet.mail.gq1.yahoo.com [98.136.217.102]) by mx1.freebsd.org (Postfix) with ESMTP id AF2A565A for ; Fri, 18 Jan 2013 20:29:09 +0000 (UTC) Received: from [98.137.12.174] by nm24.bullet.mail.gq1.yahoo.com with NNFMP; 18 Jan 2013 20:22:28 -0000 Received: from [98.136.185.40] by tm13.bullet.mail.gq1.yahoo.com with NNFMP; 18 Jan 2013 20:22:28 -0000 Received: from [127.0.0.1] by smtp101.mail.gq1.yahoo.com with NNFMP; 18 Jan 2013 20:22:28 -0000 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=yahoo.com; s=s1024; t=1358540548; bh=J5LrRcDuosRW4/BRdI9bVlOADTipuQlopLr7OlQiXn0=; h=X-Yahoo-Newman-Id:X-Yahoo-Newman-Property:X-YMail-OSG:X-Yahoo-SMTP:Received:Content-Type:Mime-Version:Subject:From:In-Reply-To:Date:Cc:Content-Transfer-Encoding:Message-Id:References:To:X-Mailer; b=n/k+MiKUgZQINb6Kpllhvc8Objzgveir/DioHdKVKxyqD9Y8bGc1GRH2waIgtZYXzVUdHctIn+TsFLiP19Srdm9FhT7B+LKM/s2wi0Y54q0+stUhNQWcpLr890fxQExFM4E026U6wqcZyqUZSBpGmZ+DvSOKVcEegDL5ZkscVGY= X-Yahoo-Newman-Id: 575620.47804.bm@smtp101.mail.gq1.yahoo.com X-Yahoo-Newman-Property: ymail-3 X-YMail-OSG: I7smv_sVM1mxLra3HhZ3Kp9aJx.w_a4ML05TZwhzXXovlu6 URbcTq5uTe4kOiqXnuMAk_MlDan4Yghuo1WLj3G7KljrRWxoNFD0T5PrXTYQ 7ui8H9xgLhi6BCCvtRRNySCC4MXR.OSKYhTM4MqaD2ointz1nQw9PpwtjkB5 evqmib0aLJD7jutGtsjcwYNmH_DE8fFo_3y2LjSKfTdq2ZrJl8CHEfvBFhRr K2Br_mMLFF2P8qLnYdypkps6BLF.T8lQb5YKXjlZt7.JjIb2CXvXg5Sc.AX5 blZhanX.PUrzKuZwrMLyi5rwxcIYrYlvaqdGlJY5G6rWNQjkKFT0k56Nzluk Lw_8smlCTmhNZ8T5LOuZ..58Vm.jn6mR6YYe6kOHojqiaO1Ar_wb6cQwRGh8 Cwzn_qyfASa9pZJ_4dW1gpniIXh40ceTTCUq_jKr3.AhOXvyQoFYJvP0MLTu 7MGACUSIgoN1YQu8zQQ70uHRg3t3YyofeMVnznhSGhm0Fvm_iZg4- X-Yahoo-SMTP: clhABp.swBB7fs.LwIJpv3jkWgo2NU8- Received: from [10.64.24.66] (scott4long@69.53.237.126 with plain) by smtp101.mail.gq1.yahoo.com with SMTP; 18 Jan 2013 12:22:28 -0800 PST Content-Type: text/plain; charset=iso-8859-1 Mime-Version: 1.0 (Mac OS X Mail 6.2 \(1499\)) Subject: Re: IBM blade server abysmal disk write performances From: Scott Long In-Reply-To: Date: Fri, 18 Jan 2013 13:22:27 -0700 Content-Transfer-Encoding: 7bit Message-Id: <6C0B86E6-195C-4D35-AE40-3D2F9F6D28FB@yahoo.com> References: To: Dieter BSD X-Mailer: Apple Mail (2.1499) X-Mailman-Approved-At: Fri, 18 Jan 2013 21:16:57 +0000 Cc: freebsd-hackers@freebsd.org, gibbs@FreeBSD.org, scottl@FreeBSD.org, mjacob@FreeBSD.org X-BeenThere: freebsd-hackers@freebsd.org X-Mailman-Version: 2.1.14 Precedence: list List-Id: Technical Discussions relating to FreeBSD List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Fri, 18 Jan 2013 20:29:10 -0000 On Jan 18, 2013, at 1:12 PM, Dieter BSD wrote: > It is inexcusable that FreeBSD defaults to leaving the write cache on > for SATA & PATA drives. This was completely driven by the need to satisfy idiotic benchmarkers, tech writers, and system administrators. It was a huge deal for FreeBSD 4.4, IIRC. It had been silently enabled it, we turned it off, released 4.4, and then got murdered in the press for being "slow". If I had my way, the WC would be off, everyone would be using SAS, and anyone who enabled SATA WC or complained about I/O slowness would be forced into Siberian salt mines for the remainder of their lives. > At least the admin can easily fix this by > adding hw.ata.wc=0 to /boot/loader.conf. The bigger problem is that > FreeBSD does not support queuing on all controllers that support it. > Not something that admins can fix, and inexcusable for an OS that > claims to care about performance. You keep saying this, but I'm unclear on what you mean. Can you explain? Scott