From owner-freebsd-current Tue Apr 4 09:28:53 1995 Return-Path: current-owner Received: (from majordom@localhost) by freefall.cdrom.com (8.6.10/8.6.6) id JAA15108 for current-outgoing; Tue, 4 Apr 1995 09:28:53 -0700 Received: from aries.ibms.sinica.edu.tw ([140.109.40.248]) by freefall.cdrom.com (8.6.10/8.6.6) with ESMTP id JAA15102 for ; Tue, 4 Apr 1995 09:28:48 -0700 Received: (from taob@localhost) by aries.ibms.sinica.edu.tw (8.6.11/8.6.9) id AAA00291; Wed, 5 Apr 1995 00:28:43 +0800 Date: Wed, 5 Apr 1995 00:28:43 +0800 (CST) From: Brian Tao cc: freebsd-current@FreeBSD.org Subject: Re: New installation notes In-Reply-To: <199504030803.BAA03823@gndrsh.aac.dev.com> Message-ID: MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: current-owner@FreeBSD.org Precedence: bulk On Mon, 3 Apr 1995, Rodney W. Grimes wrote: > > > But I were to do > > something like two 'dd if=blah of=/dev/null bs=65536' on files from > > each drive simultaneously, I should still be able to hit close to the > > maximum throughput, no? > > Depends on what maximum throughput you are trying to hit. The disk-to-bus throughput per disk. If the drives are only capable of about 2 megabytes per second, then assuming the aic7xxx driver and the AHA-2940 can handle far in excess of that, I should be able to push close to 4 megabytes per second through the bus? > I have done dual drive concurrent iozones using 3MB/sec drives and > saw a very small difference in the numbers for each drive compared > to running them seperately (ie, the bottleneck was really the drives > and not the SCSI bus, controller or PCI bus.) Right, this is what I want to determine. The bottleneck won't be the Pentium CPU, the PCI bus or the SCSI controller. I figure it's the disk, but I want to make sure it isn't the driver. -- Brian ("Though this be madness, yet there is method in't") Tao taob@gate.sinica.edu.tw <-- work ........ play --> taob@io.org