Just switched to GbE on home LAN

[bob4432]

just finalized my switch over to GbE for all of my main machines. i am having a hiccup every now and then and would like your input as to what may be causing it.

server has a pci intel pro 1000 card, laptop has a intel pro 1000 onboard nic, rig in sig has nf4 onboard GbE and the switch is a dlink DGS-2208 which is literally brand new. what i have noticed when moving large files (multiple GB) from my main rig from the server, i will get a drop out with an error on my rig saying that file is no longer available. i can then restart the transfer and it will work. but i can only transfer 3-4 files at a time, i can't grab a whole folder that may be 7GB and move it over, i will get that error.

this just started as i just finished getting my last nic yesterday. the other thing is that when moving a lot of data, this switch gets very warm, not hot, but very warm. could this have something to do with it? the switch is in a closet so moving air is not abundant.

also, there is a 100Mb/s switch connected to it to if that matters.

all cables check out ok and are either bought our made to 568A or B spec (which the switch claims it has no issue with). i have jumbo frames set to 9000 on all machines that are GbE. would there be any benefit to move to frame size of 1500? speed is important and with 9000 when it is working i am moving data @ ~40MB/s+

current drives are also installed on everything. any ideas?

indidually all looks good but when together the issue shows up. i do not have any issue when moving data at a slower speed back and fourth to the server, just when i use the max bandwidth. should i reset/power down the switch because i don't think i did that after everthing was finished.

thanks in advance 🙂

 

[Madwand1]

Well, it's nice to have a reproducible problem...

GigE switches often run warm or hot. But it's an easy problem to eliminate -- try hacking in cooling for testing. Maybe even open it up (and while you're at it, take pics of the internals and post them). If cooling is the problem, maybe you could add a heatsink / etc., or simply return it and get another model.

Some D-Link desktop switches have a performance problem with jumbo frames -- IME they cap somewhere around 700 Mb/s with jumbo frames, and can go up to at least 950 Mb/s with jumbo frames disabled. Even though you're not hitting 700 Mb/s, such a problem could still have a negative impact downwards. I'm not sure if this problem extends to the 220x series.

You can check simple performance using iperf. E.g.

server: iperf -s
client: iperf -c server -l 64k -t 21 -i 3 -r

There have been some reports on the web of such switches having performance issues when connected to 10/100 devices. Beyond cases related to excessive broadcasting, I've never seen such a problem myself.

You might also try temporary relocations with short, reliable cables to be sure that it isn't a cable-related issue.

You could also try different flow control options, to see if they make a difference.

 

[bob4432]

i have been doing some tests and here are what i have come up with so far.

i switched jumbo frames to either disabled or 1500 (depending on which nic), i unplugged the switch, turned of all the machines and plugged the switch back in and then turned on each machine individually, and i elevated the switch up a bit so air can go under it as it was much warmer (hot) underneath than on top.

what i have noticeds - i use dumeter to see what is going on and it looks like i get burst of 64KB-35MB/s up and down for about 1 minute, and then it goes full speed to ~40MB/s. is this portion normal? i am also getting what seem to be quite a bit of md5 errors regardless of what type of cable i use - either store bought cat5/e or my own - they both work equal and length doesn't matter.

does this help with trying to figure out what is the culprit? the transfers do seem to be working and finishing, just now with the md5 errors, and the errors seem to be in the first part of the transfer when it is going up and down. all have the most current drivers.

thanks in advance 🙂

 

[Madwand1]

Another random suggestion: Try taking out the switch and using a direct cable connection for some tests. It's not the same test, but if the problem's related to the switch, it should show that. Straight-though cabling should be fine for GbE.

 

[bob4432]

i will do try that out. the one thing i overlooked was that cable going to the server machine is a old regular cat 5 cable on it that had some chew marks from my cat 🙁 totally overlooked that cable. it works fine @ 100Mb/s but will be changing it out here shortly for a cat5e cable.

i will also do what you suggested and do machine to machine

thanks for the assistance

 

[spidey07]

Sounds like a cabling problem if it works fine at 100, but not at 1000.