From owner-freebsd-questions@FreeBSD.ORG Mon Aug 21 16:22:00 2006 Return-Path: X-Original-To: freebsd-questions@freebsd.org Delivered-To: freebsd-questions@freebsd.org Received: from mx1.FreeBSD.org (mx1.freebsd.org [216.136.204.125]) by hub.freebsd.org (Postfix) with ESMTP id 58E0016A4E9 for ; Mon, 21 Aug 2006 16:22:00 +0000 (UTC) (envelope-from dan@dan.emsphone.com) Received: from dan.emsphone.com (dan.emsphone.com [199.67.51.101]) by mx1.FreeBSD.org (Postfix) with ESMTP id 4C91243D60 for ; Mon, 21 Aug 2006 16:21:58 +0000 (GMT) (envelope-from dan@dan.emsphone.com) Received: (from dan@localhost) by dan.emsphone.com (8.13.6/8.13.6) id k7LGLvNQ069242; Mon, 21 Aug 2006 11:21:57 -0500 (CDT) (envelope-from dan) Date: Mon, 21 Aug 2006 11:21:57 -0500 From: Dan Nelson To: Chris Knipe Message-ID: <20060821162156.GB45306@dan.emsphone.com> References: <000701c6c539$bbb33710$0a01a8c0@superman> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <000701c6c539$bbb33710$0a01a8c0@superman> X-OS: FreeBSD 6.1-STABLE X-message-flag: Outlook Error User-Agent: Mutt/1.5.12-2006-07-14 Cc: freebsd-questions@freebsd.org Subject: Re: sluggish disk performance. 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: Mon, 21 Aug 2006 16:22:00 -0000 In the last episode (Aug 21), Chris Knipe said: > Disks ad0 ofod intrn > KB/t 16.83 %slo-z 35456 buf > tps 103 4 tfree 414 dirtybuf > MB/s 1.70 20988 desiredvnodes > % busy 98 5247 numvnodes > 4223 freevnodes > > Got 1 ATA100 Seagate 120GB disk in there at the moment.... 1.7MB/s at > 98% busy? Surely, that figure is WAY low??? I'd expect atleast > about 10MB/s on ATA100. That number's about right for random I/O and small blocksizes, which is what the KB/t field shows. If you were doing sequential I/O, the KB/t field would be at or near 128. Are you also running a "du", "cvs update", or other command likely to be doing random disk accesses? -- Dan Nelson dnelson@allantgroup.com