Date: Wed, 24 Jan 2001 21:56:09 -0700 From: "Kenneth D. Merry" <ken@kdm.org> To: Joong Hyun Kim <better@ns1.betterbox.net> Cc: hardware@FreeBSD.ORG Subject: Re: New Netgear Model GA620T gigabit cards installed, but slow speeds... any ideas? Message-ID: <20010124215609.A24460@panzer.kdm.org> In-Reply-To: <EKEPIMFMEPAAELGAIDALKEPJDJAA.better@ns1.betterbox.net>; from better@ns1.betterbox.net on Wed, Jan 24, 2001 at 10:00:42PM -0600 References: <EKEPIMFMEPAAELGAIDALKEPJDJAA.better@ns1.betterbox.net>
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On Wed, Jan 24, 2001 at 22:00:42 -0600, Joong Hyun Kim wrote: > Our company just purchased two gigabit cards to speed up transfers from one > unix file server to another unix backup server. Both systems are configured > with fast harddrives and fast hardware. I will spare the details of the > hardware since my focus is on the gigabit cards. > > Basically, we've used a Gigabit cross over (cat 5) cable. It seems to be > working fine. We can ping back and forth between the two machines using the > gigabit ethernet interfaces (ti). > > However, we're disappointed with our initial tests using ftp and nfs. They > both seem to yield less than favorable results. The speeds are a bit slower > than the two 10/100 Intel cards on both machines. Average transfer through > the 10/100 Intel for a 600MByte file is around 6.14MBytes/sec. And the > average transfer through the gigabit cards yielded about 5MBytes/sec. > > We were hoping for blazing speeds compared to the 100 Mbits/sec Intel cards. > Any ideas on what may be slowing things down? Or are we just simply using > the wrong software to test the gigabit connections? Well, first off, you should make sure you're using jumbo frames. i.e., set the MTU on either end to 9000 bytes (with ifconfig). Since you're using a crossover cable, you should have no problem with jumbo frames. (Not all switches support jumbo frames, so it might be a different story if you were going through a switch.) Second, ftp and NFS aren't the best performance benchmarks to try. I would suggest trying netperf, which is located in ports/benchmarks/netperf. Depending on the CPU power of the machines in question, I would expect at least 300Mbps performance, and possibly much more. Also, you'll probably want to increase your maximum TCP window size somewhat. Here are some parameters to tweak: sysctl -w net.inet.tcp.sendspace=262144 sysctl -w net.inet.tcp.recvspace=262144 sysctl -w net.inet.udp.maxdgram=57344 sysctl -w net.inet.udp.recvspace=65535 sysctl -w kern.ipc.maxsockbuf=2097152 The 256K window size above seems to work best with 512K Tigon boards like the Netgear GA620's. If you've got a 1MB board, like the 3Com 3c985, 512K seems to work a little better, although 256K should work fine. Ken -- Kenneth Merry ken@kdm.org To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-hardware" in the body of the message
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