How do you organise the cables in your racks?

Question

I'm migrating my current half-size rack to a full-size rack and want to take the opportunity to reorganize and sort our spaghetti-hell of ethernet cables.

What system do you use for organising your cables? Do you use any tracking software?

Do you physically label the cables?

What are you identifying when you label each end? Mac address? Port number? Asset number?

What do you use to label them?

I was looking at a hand held labeler, but the wrap around laser printer sheets might work. The Brady ID PAL seems good, but it's pricey.

Ideas?

Answer 1

Here's what I do

Label each cable
I have a brother P-Touch labeler that I use. Each cable gets a label on both ends. This is because if I unplug something from a switch, I want to know where to plug it back into, and vice versa on the server end.

There are two methods that you can use to label your cables with a generic labeler. You can run the label along the cable, so that it can be read easily, or you can wrap it around the cable so that it meets itself and looks like a tag. The former is easier to read, the latter is either harder to read or uses twice as much label since you type the word twice to make sure it's read. Long labels on mine get the "along the cable" treatment, and shorter ones get the tag.

You can also buy a specific cable labeler which provides plastic sleeves. I've never used it, so I can't offer any advice.

Color code your cables
I run each machine with bonded network cards. This means that I'm using both NICs in each server, and they go to different switches. I have a red switch and a blue switch. All of the eth0's go to red switch using red cables (and the cables are run to the right, and all eth1's go to the blue switch using blue cables (and the cables are run to the left). My network uplink cables are an off color, like yellow, so that they stand out.

In addition, my racks have redundant power. I've got a vertical PDU on each side. The power cables plugged into the right side all have a ring of electrical tape matching the color of the side, again, red for right, blue for left. This makes sure that I don't overload the circuit accidentally if things go to hell in a hurry.

Buy your cables This may ruffle some feathers. Some people say you should cut cables exactly to length so that there is no excess. I say "I'm not perfect, and some of my crimp jobs may not last as long as molded ends", and I don't want to find out at 3 in the morning some day in the future. So I buy in bulk. When I'm first planning a rack build, I determine where, in relation to the switches, my equipment will be. Then I buy cables in groups based on that distance.

When the time comes for cable management, I work with bundles of cable, grouping them by physical proximity (which also groups them by length, since I planned this out beforehand). I use velcro zip ties to bind the cables together, and also to make larger groups out of smaller bundles. Don't use plastic zip ties on anything that you could see yourself replacing. Even if they re-open, the plastic will eventually wear down and not latch any more.

Keep power cables as far from ethernet cables as possible Power cables, especially clumps of power cables, cause ElectroMagnetic Interference (EMI aka radio frequency interference (or RFI)) on any surrounding cables, including CAT-* cables (unless they're shielded, but if you're using STP cables in your rack, you're probably doing it wrong). Run your power cables away from the CAT5/6. And if you must bring them close, try to do it at right angles.

Edit I forgot! I also did a HOWTO on this a long time ago: http://www.standalone-sysadmin.com/blog/2008/07/howto-server-cable-management/

Answer 2

I saw this because of Matt's blog post, I responded to that, but here are some highlights.

Keep power cables as far from ethernet cables as possible

This is dependent on your site, but the worst cabling disasters I've dealt with are when people slavishly run power cables and ethernet cables up and down the sides of the rack. It seems like a great idea in theory, but the practice is a giant knot of either power or ethernet inside the rack post.

The best way I've found to combat this problem is to run ethernet down the center of the rack, rather than the sides.

One thing I forgot to mention before is that ethernet cables and power cables are different. That means they are run differently, have different lifetimes and different uses.

Patch Panels These are your friend. If you have a separate networking group and they don't use patch panels, it is because they don't know how to use them.

Patch Panels -- The Bad Yes, they take up space in your rack, yes they limit the amount of available ports per rack. Putting them in is more work. I will also admit they are not appropriate for every site.

Patch Panels -- The Good Tracing cable runs of 6 feet or less is exponentially easier than tracing cable runs of 12 feet or more. Adding in new equipment is easier, no more fishing cables through 15 different runs. This can limit the amount of crap that gets shoved into one rack (sometimes this is good).

It is a fact of life that servers move frequently comparative to other datacenter equipment. All your old cable drops just add to mess you have to deal with. Since power cables are confined to the rack and can always be reused, this keeps the clutter buildup down.

Most of the frequently cited bad issues with patch panels can be mitigated through planning appropriately.

Raised Floors Can still be a good thing in some cases. NEVER put network drops under a raised floor unless you hate your coworkers and plan to leave soon. If you have a raised floor only use it to run power cables.

Ladder Racks Overhead cable runs are the only way to preserve your sanity or blood pressure. This is especially true if you don't use patch panels.

Answer 3

I think this a very similar question to these:

Cable Management Policy
How to keep your physical server environment manageable

The only thing I have to mention, use velcro tie wraps.

Answer 4

As far as what to label the cables with - I would stay away from anything specific like hostnames or mac addresses, since the cables/switch ports will likely be re-purposed over time.

But DO label them with something - numbers seem the obvious choice.

Label both ends the same, and ensure there are no duplicates. This makes tracing cables a whole bunch easier, and alleviates much of the concern of bundling a bunch of cables together into a neat run. We even label our short (1 foot) cables, and then bundle them into bunches of 10-20 - and it makes it MUCH easier to identify which cable is which.

Another option would be colored cables - but that gets to look messy.

Answer 5

• Label everything. The Brady ID Pal is what I use and is worth the cost
• Power down one side of the rack, network on the other
• Use a KVM over CAT5 solution if you can, reduces cable clutter tremendously. Use one color CAT 5 for your KVM cables, another for your network.

For LAN wiring, I've used a method of bunches of 8 cables, each a different color going from patch panel to switch. 48 port patch panels to 48 port switches. With the different colored cables, it is VERY easy to trace a single cable without pulling it out and makes everything look very very nice.

With some inline here for good measure

alt text http://photos-a.ak.fbcdn.net/photos-ak-sf2p/v248/20/63/1067293293/n1067293293_62808_2066.jpg

During http://photos-b.ak.fbcdn.net/photos-ak-sf2p/v248/20/63/1067293293/n1067293293_65873_693.jpg

alt text http://photos-h.ak.fbcdn.net/photos-ak-sf2p/v248/20/63/1067293293/n1067293293_67279_5546.jpg

Good luck! I think excellence in wiring is a strong trait for any sysadmin. Presentation is a big part of any job and having well dressed racks goes a long way to showing non-technical people that you're on top of your game.

Answer 6

Velcro bundles together, avoid zip ties like the plague. Measure how long you need your cables to be and cut them to size, accounting for slack, and how you want to run them.

When you rewire, do it right the first time.

Label where every cable came from, and is going to, BEFORE YOU TOUCH ANYTHING!!!

when all is said and done, unplug it all and start from scratch at 2am like the rest of us :D

As for labeling where cables are going to/from, if your server/wiring room is on lock down, feel free to label every little bit and piece. If parts of it are exposed to users, label nothing but have it all diagrammed out.

Answer 7

Here is what we do for our networking rack. We are a small company so we don't have that many switches, but it keeps things clean.

Core Switch
24pt patch panel
48pt access switch
24pt patch panel
24pt patch panel
48pt access switch
24pt patch panel

Each patch panel has the first port blank. The 23 remaning ports are connected to the nearest switch (either up or down) with 1ft cables. We leave them un-labelled since they are so short they can't get tangled. This fills up the switch while leaving two ports for uplink to the core at the top. These uplinks are labelled, and put into LAG membership.

The pattern continues down for all switches, leaving a simple layout, that is easy to trace and replace cables.

Different colour cables are used for printers, hosts and uplinks to make it easily identified.

A separate document is kept that matches patch panel port (effectiely the wall jack number) to a specific switch, and is compared against the office map (with wall jack number labelled) for troubleshooting.

Answer 8

We're lucky, we use HP's 'Virtual Connect' for all of our cabling, which has reduced our in-rack cabling by a factor of 16 or something - but we always make a point of really clearly labelling every cable - and never with a server's 'soft' name, only ever with their physical location - this doesn't change but the server's function, and thus 'soft' name often does.

Answer 9

We're just moving our datacenter cross city in a couple of months. I started shortly after the server room had been agreed with the architect, but there are a few areas where I could change things.

We have about 100 servers moving along with our SAN (7 racks in all). We will be using cable trays above the racks to carry our CAT 6 cabling to our core switch. These will be structured cabling - patch panels in the server rack and core rack. We will be using two nics in each server. Our I/O (networking & fiber) will be running on the right-hand side of the rack while power will be running on the left.

Power to the cabs runs under our raised floor while the networking runs over head - separating out power and networking. We use bought cabling for patch leads but we will be terminating the cat6 patch points ourselves.

We will be labeling all the cables at all ends (svr -> patchpoint) (patchpoint -> core), we use a standard labeler and secure it around the cable, rather than a 'tag' like one. It makes it easier to read. We don't currently use any software for tracking.

Answer 10

The general good practice seems to be to identify port numbers on each jack endpoint, use bundles of short cables to patch between panels, and keep a database / text file of computer-port number assignments.

A hand held labeler works fine for port numbers, feel free to use hex if it saves you space...

The cables themselves are not generally labeled.

Answer 11

I like the methods outlined in the accepted answer better, but here's how I've been doing it myself. I rarely have the luxury of dual NICs, so each machine has just one ethernet connection: workstations are blue, servers are green, uplink is yellow, Internet is red.

I label both ends with my Dymo handheld labeller. I prefer to run my labels along the wire, using clear tape to keep them from peeling off easily. More work, but nicer results. I run ethernet along the front side of the rack - left or right depends on which is closer. Power runs down the back of the rack.

I prefer Velcro straps, but IBM requires zip ties. Usually white, but sometimes black if the customer requires it (apparently white zip ties have been confused with french fries).