From owner-freebsd-hardware Fri Sep 22 12:09:41 1995 Return-Path: owner-hardware Received: (from root@localhost) by freefall.freebsd.org (8.6.12/8.6.6) id MAA14788 for hardware-outgoing; Fri, 22 Sep 1995 12:09:41 -0700 Received: from parmenides.cfar.umd.edu (parmenides.cfar.umd.edu [128.8.132.3]) by freefall.freebsd.org (8.6.12/8.6.6) with ESMTP id MAA14783 for ; Fri, 22 Sep 1995 12:09:38 -0700 Received: from empedocles.cfar.umd.edu (empedocles.cfar.umd.edu [128.8.132.6]) by parmenides.cfar.umd.edu (8.6.8.1/8.6.6) with ESMTP id PAA00623; Fri, 22 Sep 1995 15:09:34 -0400 Received: (cvance@localhost) by empedocles.cfar.umd.edu (8.6.8.1/8.6.6) id PAA09697; Fri, 22 Sep 1995 15:09:16 -0400 Date: Fri, 22 Sep 1995 15:09:13 -0400 (EDT) From: Chris Vance To: hardware@freebsd.org, Bruce Evans Subject: Re: Adaptech 1542 & 3Com 3c509 conflict? In-Reply-To: <199509221125.VAA03283@godzilla.zeta.org.au> Message-ID: MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: owner-hardware@freebsd.org Precedence: bulk On Fri, 22 Sep 1995, Bruce Evans wrote: > >I seem to have some sort of conflict between my network interface and > >scsi disks. The scsi controller is an adaptech 1542CF and the eth > >adapter is a 3c509. > > >Basically, the network is slow writing to a scsi disk, and fast the > >rest of the time. Has anyone seen this before? Can anyone suggest > >something I could do to fix the situation? > > Perhaps the scsi disk is inherently slower for the type of work given > to it by ftp. This is not unlikely, since ftp's writes are poorly > buffered and scsi disks often have a very high command overhead. I don't think this is it at all. As I mentioned, I've also run iozone while ftping a huge file to /dev/null, and the iozone results are within 100kps of the normal speeds, however the network speed plummets to 200kps. (normally ~500-600kps to /dev/null) > The speed over ethernet (WD8013EBT) for ftp'ing a 15MB file to a slow > scsi disk and to /dev/null were the same (about 440K/sec, probably > limited by the slow IDE disk on the server). This was faster than for > ftp'ing from localhost and the same speed as cp'ing from the same file > system in some cases (cases where the buffer cache cannot help and > where clustering is apparently ineffective). I just ftp'd to localhost, and got 745kps reading and writing to the same scsi disk and 1.29MB/s writing to /dev/null. I feel that it's definitely a conflict between the 3c509 and the adaptech. If anyone needs additional info to help diagnose the problem, I'm certainly willing to provide it. I really want to find a solution to this problem. chris.