From owner-freebsd-scsi Fri Feb 12 08:02:41 1999 Return-Path: Received: (from majordom@localhost) by hub.freebsd.org (8.8.8/8.8.8) id IAA29190 for freebsd-scsi-outgoing; Fri, 12 Feb 1999 08:02:41 -0800 (PST) (envelope-from owner-freebsd-scsi@FreeBSD.ORG) Received: from panzer.plutotech.com (panzer.plutotech.com [206.168.67.125]) by hub.freebsd.org (8.8.8/8.8.8) with ESMTP id IAA29176 for ; Fri, 12 Feb 1999 08:02:27 -0800 (PST) (envelope-from ken@panzer.plutotech.com) Received: (from ken@localhost) by panzer.plutotech.com (8.9.2/8.8.5) id JAA34641; Fri, 12 Feb 1999 09:02:18 -0700 (MST) From: "Kenneth D. Merry" Message-Id: <199902121602.JAA34641@panzer.plutotech.com> Subject: Re: It%s not the write cache on 3.0-STABLE and not tagged comma In-Reply-To: from Matthew Jacob at "Feb 12, 1999 5:57:40 am" To: mjacob@feral.com Date: Fri, 12 Feb 1999 09:02:18 -0700 (MST) Cc: ANDREAS.KLEMM.AK@bayer-ag.de, scsi@FreeBSD.ORG X-Mailer: ELM [version 2.4ME+ PL43 (25)] MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: owner-freebsd-scsi@FreeBSD.ORG Precedence: bulk X-Loop: FreeBSD.org Matthew Jacob wrote... > > What was the problem? He is getting poor performance for sequential writes with a Seagate disk under CAM. Write throughput to the disk is fairly erratic. (i.e., lots of ups and downs) He has the problem under 2.2.7 with tagged queueing enabled, but not when he disables tagged queueing. The problem occurs under 3.0 with or without tagged queueing. I told him to disable write caching, since I have seen similar problems when write caching is enabled, but that didn't seem to fix the problem. Any ideas? Ken -- Kenneth Merry ken@plutotech.com To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-scsi" in the body of the message