Date: Wed, 18 Sep 2002 10:55:27 +1000 From: David Burns <david.burns@dugeem.net> To: Steve Fettig <lists@stevenfettig.com> Cc: net@FreeBSD.ORG Subject: Re: Network Transfer Speed Issues - Tweaks/Advice? Message-ID: <3D87CEFF.1010409@dugeem.net> References: <DEC874D3-C763-11D6-9524-00039384AB84@stevenfettig.com>
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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
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