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network slow and hanging after renovation? emi issues?

Posted on 2013-06-18
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Last Modified: 2016-11-23
It's been 2 months, i have an office that was running perfectly before we renovated.  Now we are having nothing but random freezing issues and machines locking up while they sit. only thing extra we had put in the server room is  a sonos system for music and a air duct to get hot air out and a thermostat.

 

I am the network admin trying to narrow down issue that they have been having for   a month. You come to the machine, its on and has power, by moving the mouse and hitting keyboard no video will display. No key seq like crtl alt delete with work.  After one froze and i was there I ho0oked up another keyboard, mouse(usb), and new monitor, all new dell vostro's. still nothing.  funny part is it is NOT a pc issue.  I brought them back to my shop and they ran for a week with no issues here just sitting on the desktop, video came back fine every time. It has to be something in that environment?  Some pc's are fine and others are having nothing but issues.  I even put new temp pc's in their place and the temp pc's have issues (same issues) while they are in that environment but not if they run at our shop?? All computers have avg business edition 2012 or 2013.

 

We are also experiencing slowness on the network at random times to random computers.  I have troubleshot everything from our 1 physical server that runs virtual. i have made some changes with the hyper-visor and no better. i have called cisco and went over our asa 5505 and vpn tunnels, made adjustments, no better.  went over out 48 port switch, firmware updates and no improvements. went out and bought another one from different manufacturer and still no better??  I've been getting complaints, it is slow from all 3 offices but was running smooth before renovation and sonos, in all 3 locations.  

All they do is rdp into our ts and run 1 program, the sessions always stay up but the application which depends on sql may freeze, or really mean hang. in the mean time i had made up a batch file that i wanted them to run while they were waiting for the application to respond at the main location where the server is and 99% of the time response is 1ms.  we have allocated 40gb to the sql server and 18gb to the ts for about 60 users total in all  3 locations. I and the other company that we use for software has gone over server, memory, paging, resource monitor etc and cant find anything?

More troubleshooting- we checked(cable tested) and labeled every wire in main location and made sure it was dhcp unless a needed static and we get no ip conflict errors on any machine.
I am starting to think since we ran all utp cat 6 that we are getting emi because of the renovation.  they redid the whole ceiling and moved everything around? I assume that would affect the whole main location but since the server is plugged into same switch it could affect other locations?  Also if is was emi, how do i narrow it down to what device? what can i put around it to block emi? Most important, how far away should the cabling be from electrical 120v power, 2.4 wireless access points, florescent lighting(4 or 8 ft tubes)? could the thermostat in the server room cause an issue?  

please help and be explain as much as you can. i don't know what else to look for.
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Question by:bowlerman25
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by:giltjr
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What brand and model switch do you have?

If its a Cisco switch can you reset the counters on each port and then do show int for the sever and a few of the other ports to see if they are encountering errors.  If there is EMI, then you should see error counters start going up.

What I have always been told is that if power is running  parallel to  unshielded network cables that it should be at least 6 inches away.

I believe that it should also be at least 6 inches away from florescent lighting.
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by:bowlerman25
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i had a cisco sg200-50p but i have switched it out for now with a netgear 48 port gs748t. anything else i can check?
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by:bowlerman25
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i am on site and they have a electrical motor that is about 1 ft away from where all the cabling comes into the patch panel through a ceiling tile.  they put it in new after renovation. the room has a vent in the drop ceiling to take the hot air out of the room and put it above the ceiling.  since the motor is so close, could that cause an issue with the utp cabling? here is a picture
motor.jpg
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by:jensenjl
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Have you tried turning off the blower at the circuit breaker?

The cabling you have pictured does not follow best practice methods for structured cabling.  It looks like some of the cables are wrapped around the conduit, laying on the metal studs and not in cable hangers.  Is the rest of the cable in the ceiling placed in a similar fashion?  

Cable should also not lay on the ceiling tiles nor across fluorescent lights.  The lights emit a significant amount of interference and can cause quite a fair amount of network issues.

If the cable must cross power lines/conduit it should do so at a 90 degree angle and not run perpendicular to electrical lines to reduce interference.

Do any of the cable runs exceed 100 meters?  Ethernet runs (end to end including patch cables) are not supported in excess of 100 meters.
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by:bowlerman25
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i know some of the cabling are not in hangers, we did not do all of it. what we  did is all above the ceiling.  the blower has a thermostat in the server room, i have it turned all the way up for just tomorrow so it does not turn on.  none of the cabling exceeds 100 meters, that i know well. thanks for the info.  i spent a while with citrix on the phone and found something wrong with the driver on the hypervisor, i think that may have corrected the speed issue, i will follow up.
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by:giltjr
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Depending on what the motor spec's are, it could definitely cause problems.

I remember a story about a large sun server that was installed new and shortly there after would randomly crash.  Might be 5 times a day one day and then go a week without crashing.  After weeks of trouble shooting and replacing darn near the whole box the hardware engineer was standing in front of it when it crashed once.  He also noticed a "loud noise" coming from the wall.  Found the server was right next to a wall that backed up to the elevator shafts.  These were old elevators that had the big electrical motors on the top.  When both elevators passed the back wall at the same exact time there was enough EMI to corrupt memory.  Corrupt the "right" spot and system crash.  Solution was to move the servers away from the wall 18 inches.
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by:TomRScott
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I would check the UPS logs (assuming you have some somewhere) looking for brown-outs.

I like the idea of flipping the breaker on that motor too. If you have to, put a cheap fan in the room and leave the door open if security allows.

The wiring could be neatened up a bit, especially moving some of the closer cables a little farther from the motor.

However, my main suspicion would be power issues introduced by the renovation. Were other power draws added to the circuits? Might there be a power fault introduced, bad grounding, etc?

 - Tom
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by:aleghart
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How did you test the cables?  I can see a couple that are kinked already.  If the outer jacket is wrinkled, then the bend radius is too tight.  Also, you can see drywall screws left in place, with the drywall having been ripped out.  So...not a gentle renovation job.

Do you have something like a Fluke CableIQ that can test for shorts, breaks, and mis-wiring?  I traced down a few salvageable ports that just needed to be trimmed back and re-termininated.  Another had a screw driven through the jacket during a drywall repair.  A single wire was broken, and we had to abandon the cable in-place.

Did you already look for accidental loops?  Turn on spanning-tree protocol?

Is your core switch a Layer2 or Layer3?
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by:bowlerman25
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we have solved the issue, it was not the wiring at all. the xenserver had a problem with the nic driver causing a lot of packet loss. that was the main issue. other issue was motor being too close to the wiring. causing some issues also.  the exhause fan is getting moved away from the wiring.
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by:TomRScott
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Not to be too pointed, but RFI/EMI being introduced into your wiring is, by definition, a type of wiring problem. Which you appear to be addressing by moving the exhaust fan motor.

 - Tom
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by:bowlerman25
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OK but that's because its utp correct? if i had stp this would not happen?
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by:TomRScott
TomRScott earned 250 total points
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STP certainly helps depending on how strong the interference may be AND if installed properly with the shielding grounded properly or it can actually aggravate the situation.

Here is a nice primer on UTP vs. STP:
- Tom
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jensenjl earned 250 total points
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If you have a device that is electrically noisy you wouldn't necessarily need to replace all of your UTP with STP.  It would likely be more economical to shield the device or move it a safe distance away.

However the cabling could use some cleanup.  Tidy cable is easier to manage.  It might be easier to protect that area from EMI as well if it were not so spread out.
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by:bowlerman25
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that's why we are moving the motor
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