You need all 8 wires fool

I’ve been a bit disappointed with the performance of my system for a while. I run an sd11g5 from shuttle which is a Pentium M based machine. I run it diskless. I read the NFS howto and decided to try increasing the rsize and wsize parameters when mounting my filesystems. Normally when I boot my PC I start it up and walk away. I have gdm configured to automatically log me in (it’s a home machine, don’t give me crap about security). I wanted to watch the kernel output today to see if anything different happened with the rsize and wsize options set at 32768. I saw something which really surprised me. I saw a 100 Mbps link negotiation. I should have been getting a 1000 Mbps link. I know that I used to.

After rebooting the switch a few times and verifying that it wasn’t the switch I headed back to my PC. I did some googling and then it dawned on me – it could be the cable. I wired my entire house with cat6 cable but I didn’t worry about having cat6 for patch cables (although most are because I’ve made them from the 60 feet of spare cable that I have). Sure enough I saw only 6 wires terminated on the patch cable I’ve been using for a VERY long time. Gigabit ethernet requires all 8 wires. I think, to keep myself sane, I should throw out that patch cable (but I won’t because I’m cheap and because I have a couple 100 Mpbs devices on my network).

My machine is performing much better than it has for quite some time. I don’t know how much of an effect the rsize/wsize tuning made because I’m sure the speed increase from 100 Mbps to 1000 Mbps far overshadows a block size improvement. Still, I’m curious so at some point I will probably remove the rsize/wsize parameters and see if the machine is noticably slower.

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