From owner-freebsd-bugs Wed Apr 5 19: 6:50 2000 Delivered-To: freebsd-bugs@freebsd.org Received: from caspian.plutotech.com (caspian.plutotech.com [206.168.67.80]) by hub.freebsd.org (Postfix) with ESMTP id 4B4D637B80C; Wed, 5 Apr 2000 19:06:44 -0700 (PDT) (envelope-from gibbs@caspian.plutotech.com) Received: from caspian.plutotech.com (localhost [127.0.0.1]) by caspian.plutotech.com (8.9.3/8.9.1) with ESMTP id UAA24407; Wed, 5 Apr 2000 20:07:26 -0600 (MDT) (envelope-from gibbs@caspian.plutotech.com) Message-Id: <200004060207.UAA24407@caspian.plutotech.com> X-Mailer: exmh version 2.1.1 10/15/1999 To: mjacob@feral.com Cc: Andrew Heybey , freebsd-bugs@FreeBSD.ORG, freebsd-scsi@FreeBSD.ORG Subject: Re: kern/17153 (was: newfs on IBM disks slower than Seagate disks?) In-Reply-To: Your message of "Wed, 05 Apr 2000 18:59:28 PDT." Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Date: Wed, 05 Apr 2000 20:07:26 -0600 From: "Justin T. Gibbs" Sender: owner-freebsd-bugs@FreeBSD.ORG Precedence: bulk X-Loop: FreeBSD.org >> Newfs of a ~16GB partition (as performed by sysinstall, so the newfs >> arguments are the same) is *much* slower on IBM 18GB 10K RPM LVD disks >> versus similar Seagates. Systems are otherwise identical (same >> controller (onboard Adaptec AIC7896), same motherboard, same amount of >> RAM). Once newfs'd, bonnie and iozone give similar performance for >> the two disks. Rawio also gives similar numbers for the two. >> >> Running 3.2-RELEASE. >> >> IBM disks are DMVS18V. >> Seagates are Cheetah ST318203LW. >> >> Why would this be the case? IBM usually ships with the write cache disabled. Seagate almost always has it enabled. As newfs is a "single blocking I/O at a time" kind of application, the additional write latency causes a degradation in performance. When going through the filesystem, this latency is hidden by the buffer cache. You can view mode page 8 with camcontrol to determine the settings for your drives. Man camcontrol for details. -- Justin To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-bugs" in the body of the message