Jumbo Frames

[uteck]

Not your glasses, but your packet size. Does size really matter? Let's ask Smilen' Bob. First I checked if my switches would support an MTU of 9000, and the specs at the manufactures site said they would. The problem came with my network cards. They would not take a setting of 9000. Turns out their max is 7200. Still better then 1500, so lets test it with a 243M file at 7200; 1m29.935s, not bad.
Now lets reset to 1500 and try again; 0m51.368s. See, clearly size does....wait a momnet, this was much faster. Perhaps some inode caching going on? Lets try at 7200 again' 0m50.911s. Hmmm.

Okay, lets try with 2 different files of the same size of 175M. First at 7200; 0m47.007s, now at 1500; ... and again.... Dammit my fileserver keeps crashing, good thing I got this new one. Now if I can just copy over the files. Again; 0m39.368s.

There we go, proof that size does not matter. And I sooo wanted to brag about my frame size, but it apparently is a bit slower. Oh well, it was a good learning experience. Perhaps a stable fileserver will improve my network performance?

[uteck]

Turns out one of the disks in the new server was bad and was causing NFS errors. After a few days, it finally died. The nice people I bought it from are sending out a new disk. Running the array in degraded mode seems much better then when all 4 disks were working.
When I get the new disk installed I'll run the tests again and see if the bad drive made a difference.

Here are some referances so people may know what I am talking about. I had them in befor, but the browser locked up before I could post the orignal and I forgot to add them again.

http://sd.wareonearth.com/~phil/jumbo.html
http://en.wikipedia.org/wiki/Jumbo_Frames
http://www.connectathon.org/talks98/GbE-cthon.pdf