First, I switched internet carriers from AT&T U-Verse to Comcast.  I bought my own modem and ASUS AC66U router.  Everything works, but every hour my server loses connection.  This is my network to the server.

 

Comcast ---- Asus AC66U-----Netgear 8 port switch ----- Trendnet 8 port switch ---- Server

 

Now, I removed the Netgear switch, and now my network to the router is as follows

 

Comcast ---- Asus AC66U ---- Trendnet 8 port switch ---- Server

 

 

I apologize for not saving / downloading a system log before I rebooted my server.  I will monitor this new set up for the next hour or so to see if the "lost carrier" error happens again.  I've got a pretty strong feeling that the Trendnet switch might be the culprit.  I had some issues before with this switch not being able to connect at gigabit, but now I am in need of a switch and this is what I had laying around.

 

So, if it happens again, I am going to have to get a different switch and test it.  IT SHOULD BE NOTED: I AM USING A PCI Intel® PRO/1000 Network.

 

I had to switch to RC12a since unmenu would become unresponsive whenever I spin down / up the hard drives.  After over an hour of my server being on, I haven't seen any "carrier lost" issues.  It appear that the new network set up or reverting back to RC12a has hopefully fixed this issues.

 

I wonder if this would be the reason why the movie my son was watching yesterday started to fast forward and get out of sync.

syslog-2013-07-03.txt

Nope, my server still having the "carrier lost" issue.  I am going to switch the netgear switch with the Trendnet.  This sucks.

syslog-2013-07-03_1.txt

Can you try the onboard NIC on your motherboard just to rule out the problem is not the NIC?

Can you try the onboard NIC on your motherboard just to rule out the problem is not the NIC?

 

That's going to be my next move.  Right now, I removed the Trendnet switch, and move my Netgear one to the unraid.  If that doesn't work I will try out the onboard NIC. 

It's been 6 hours, and no "carrier lost" errors.  Crossing my fingers!!!

10 hours and everything is looking good.  I will keep the server on may be for another 40 hours or so, and keep checking the system log.  It appears that I will be needing a new gigabit switch.

  Sounds like you found the problem then... Of course, you never know for sure unless it happens again, then you can probably assume you did not find the problem, or you have multiple issues... oh, the fun of intermittent problems.  At least your problem was occuring rather regularly.  :-)

 

  I also have a TRendnet Gb switch I retired some time ago, it was acting much like you describe.  I did not notice if the timing of disconnects was consistant like you had or not however.  I remember running in circles a little while with it too...

 

 

I agree it is a PIA to work with network issues. It has been 24 hours, and I didn't noticed an "carrier lost" issues. I will post it has resolved.

 

Now, I will be replacing both of my Trendnet switches with Netgear ones.