From owner-freebsd-net Tue Sep 17 17:55:50 2002 Delivered-To: freebsd-net@freebsd.org Received: from mx1.FreeBSD.org (mx1.FreeBSD.org [216.136.204.125]) by hub.freebsd.org (Postfix) with ESMTP id 7D8FF37B401 for ; Tue, 17 Sep 2002 17:55:49 -0700 (PDT) Received: from mail016.syd.optusnet.com.au (mail016.syd.optusnet.com.au [210.49.20.174]) by mx1.FreeBSD.org (Postfix) with ESMTP id 6D44943E8A for ; Tue, 17 Sep 2002 17:55:48 -0700 (PDT) (envelope-from david.burns@dugeem.net) Received: from dugeem.net (c19426.carlnfd1.nsw.optusnet.com.au [211.28.175.9]) by mail016.syd.optusnet.com.au (8.11.1/8.11.1) with ESMTP id g8I0tia17749; Wed, 18 Sep 2002 10:55:45 +1000 Message-ID: <3D87CEFF.1010409@dugeem.net> Date: Wed, 18 Sep 2002 10:55:27 +1000 From: David Burns User-Agent: Mozilla/5.0 (Windows; U; Windows NT 5.1; en-US; rv:1.1) Gecko/20020826 X-Accept-Language: en-us, en MIME-Version: 1.0 To: Steve Fettig Cc: net@FreeBSD.ORG Subject: Re: Network Transfer Speed Issues - Tweaks/Advice? References: Content-Type: text/plain; charset=us-ascii; format=flowed Content-Transfer-Encoding: 7bit Sender: owner-freebsd-net@FreeBSD.ORG Precedence: bulk List-ID: List-Archive: (Web Archive) List-Help: (List Instructions) List-Subscribe: List-Unsubscribe: X-Loop: FreeBSD.org Steve Fettig wrote: > > I recently set up an NFS server to run daily backups on. The server was > built using an old P150 w/ 90 MB of ram and a 6GB hard drive. (All > servers in this experiment are set up using FBSD 4.6.2 and the client is > a Mac PowerBook G4 running Mac OS X.) Attached to it is an external > SCSI hard drive enclosure with 4 47GB SCSI drives running off an > AHA-2490UW SCSI adapter. I am getting really odd performance when doing > an NFS transfer (I also get odd performance out of scp) from the machine > I am trying to back up. I will get a burst of 20Mbps for about 30 > seconds, then it will ramp down to 1 Mbps for about 2 minutes, ramp > backup to 20 Mbps, then back down to 1 Mbps and so on. > You need to break the problem down ... Is the system CPU and/or IO bound during the backup? Also try some quick benchmarks to verify basic system performance levels: Network IO - use ttcp (or netperf etc), and Disk IO - use bonnie (or similar). NB Of course you can't simply take such benchmarks results and put them together - but you will gain a better understanding of where the potential slowdowns may be. Lastly, performance issues on older Pentiums can also result from poor memory bandwidth and/or PCI chipset problems. I recently replaced a P120 with a Celeron 333 - the performance improvement was surprising. Regards, David To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-net" in the body of the message