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I'm looking at rewiring our server room to be more presentable, organized, and easier to troubleshooting.

Right now we currently have 4 HP racks (don't know the model right now). We do not have a building UPS so we are placing UPS's in each rack (10K, 5K). This is causing a lot of mess but I unfortunately do not have another way to do it. We also do not have raised floors.

One of my racks contains the firewalls, network switches, and fiber switches. Currently we are running cables from our main switch to all of the servers / SANs in the other racks (directly). The other racks contain mostly servers with one that also has a SAN in it.

Here are my questions:

  • Should I place a patch panel in each rack and run cables from our main switch to the patch panels? Then connect each server to the patch panels that are in their own rack?
  • Right we have the air conditioning pointed down the aisle where the front of the racks (preparing for hot aisle / cold aisle setup when we expand). Reason I am bringing this up is because our switches are in the front of the racks instead of the back. Should I place the switches and patch panels in the back or front?
  • If I place the patch panels in the front of the rack what is the best way to run the cables from the rear of the servers to the patch panels? I can't really access the sides of the racks (open the panels) because other racks are touching.
  • For the power situation we currently have two HP PDU's that connect to HP Extensions bars in each rack. These are located on the left side and the LAN cables on the right. I do have a mixture of servers that have the power supplies on the left and some are on the right. So having the extension bars and PDUs on the left and right would be great but I've read you should keep the CAT cables and power separated. Should I continue to do this?

If you think I missed any questions please let me know! Thanks in advance!

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1 Answer

I'd suggest a cabling contractor. Seriously. It helps to get some ideas of what other installations look like, and they can help guide you.

In your case, you probably have HP 10642 or 10642 G2 racks.

To answer your questions...

  • Standard practice is to place your top-of-rack switches and patch panels at the rear of the cabinet. You didn't specify the particular types of switches in use. Please provide that information.

  • Depending on your switch models, they may pull air in from the sides, rather than the front or rear of the device, so place them where it makes sense from a cabling and servicing standpoint.

  • Don't place your patch panels on the front of the rack if you have a choice. You totally want to avoid this situation before it gets too unwieldy.

  • You don't necessary need to keep power and data cables separated, but it's probably good practice to do so. For your power cable situation, buy short power cables.

Some examples...

Front view - Data center fiber patch panel in front. All switches and router rear-facing. Servers are front mounted. enter image description here

Rear view - Switches and router are rear-facing. Cabling run in channel behind rear vertical rails. enter image description here

Another front view. Switch chassis is mounted along rear rails. enter image description here

Another rear view. All patch panels and cabling are rear-faacing. enter image description here

Use appropriate length power cables to connect to your power distribution units. The location of your servers' power supplies shouldn't matter since you can run the right-sized cable to the PDU. pic

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Thank you for the information! –  Jacob Dixon Apr 14 '13 at 1:38
    
We have a HP Procurve 4108GL switch as our main switch. This currently is the only switch. So if I'm understanding you correctly I should put the switches, firewalls and patch management in the rear. I should then use patch panels in all the other racks to connect to the main switch. I'm afraid a cabling contractor is most likely out of the budget :-( but you have given me enough information to go off of. We curretly have routers, switches on the front due to hot isle, cold isle setup but I dont believe they put out much heat so it should be ok to turn them around –  Jacob Dixon Apr 14 '13 at 1:42
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For chassis switches like the ProCurve 4200vl and 5400zl series, I this the critical fans are on the side. Really, the switches should be in open 2-post telco/relay racks... But if I'm stuck with an enclosure, I place them on the rear of the rack. –  ewwhite Apr 14 '13 at 1:49
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