Cables labeling

Arseni Mourzenko
Founder and lead developer
December 12, 2014
Tags: hardware 11 datacenter 4 cables-management 1

Re­cent­ly, I was adding new serv­er hard­ware. I took it as an op­por­tu­ni­ty to rewire all net­work ca­bles. This ar­ti­cle ex­plains how the task was per­formed.

Ca­bles man­age­ment is like reg­u­lar back­ups: every­body (by every­body, I mean peo­ple who ac­tu­al­ly deal with serv­er hard­ware) knows this is im­por­tant, but most peo­ple are too lazy to do it. And just like with reg­u­lar back­ups, when ca­bling man­age­ment is not done prop­er­ly or at all, it may—and prob­a­bly will—trans­form it­self into a big headache and a lot of waste of ef­fort an mon­ey.

I start­ed to do ca­bles man­age­ment years be­fore pur­chas­ing my first rack serv­er. I re­mem­ber my­self crawl­ing un­der the table in my bed­sit rerout­ing ca­bles or spend­ing hours at night gaz­ing at spaghet­ti ca­bling im­ages (is that pornog­ra­phy for geeks?) or read­ing about ca­bling man­age­ment in real data cen­ters.

Years passed, and I'm now tak­ing care of a con­fig­u­ra­tion con­sist­ing of two servers, one work­sta­tion, two UPS units and one switch.

But I di­gress. Let's talk about ca­bles-re­lat­ed stuff.

Step 1
Tem­po­rary la­bel­ing


An es­sen­tial step is to de­ter­mine which ca­ble does what, and to la­bel it. It is es­sen­tial be­cause if you don't, you may find your­self rout­ing ca­bles to the wrong di­rec­tion, and you prob­a­bly don't want to redo all the hard work.

The fastest and in­ex­pen­sive way I've found to tem­po­rary la­bel ca­bles is to use post-its. Since they de­tach eas­i­ly, one can sta­ple them like shown on the pho­to above. Sta­ple it close enough to the ca­ble to pre­vent the post-it from slip­ping from the end­ing of the ca­ble, but be care­ful to not dam­age the ca­ble it­self.

The ca­bles should be tem­po­rary la­beled on both sides. All ca­bles should be la­beled, even the ones which al­ready have a la­bel which will re­main un­changed.

Step 2
Tie the ca­bles


Now it's time to group ca­bles to­geth­er. De­pend­ing on the num­ber of ca­bles and com­bi­na­tions, it may re­quire to do it on pa­per first. In my case, I just made an in­for­mal ba­sic schema show­ing where do dif­fer­ent ca­bles go.

Then I used ca­ble ties to group the ca­bles and cut tie end­ings. I'm un­hap­py with the re­sult, be­cause it be­comes easy to cut one­self with the tie, but I don't know any bet­ter way to do it. When I look at the pho­tos of data cen­ters on in­ter­net, I have an im­pres­sion that the end­ings are cut very close to the head. I don't know how this is done.

Step 3
Route the ca­bles


The next step con­sists of rout­ing the ca­bles through the rack and out­side of it. In­stead of a in­dus­tri­al rack cab­i­net, I have an open frame rack which has noth­ing for ca­bles man­age­ment. A bit of imag­i­na­tion helped rout­ing the ca­bles from the switch on the front to the back of the rack, but I wouldn't be able to do it with more ca­bles.

This showed me how im­por­tant is to get a real rack cab­i­net. Us­ing patch pan­els could have solved a few prob­lems, but still, even ver­ti­cal­ly, it would be dif­fi­cult to route the ca­bles in a non-in­tru­sive way.

Post-its were also slight­ly an­noy­ing be­cause I had to route the ca­bles through the holes in the rack cab­i­net. With an in­dus­tri­al rack cab­i­net, this wouldn't be an is­sue.

Step 4
Re­place tem­po­rary la­bels by per­ma­nent ones


Once the ca­bles are prop­er­ly rout­ed, the last step is to re­move tem­po­rary la­bels one per one, and re­place them by the per­ma­nent ones. I use Broth­er QL-700 to print la­bels, but any oth­er la­bel print­er will do the trick. On the oth­er hand, you do need an ac­tu­al la­bel print­er.

It's up to you to de­fine what will the la­bel con­tain. In my case, it has the name of the source and of the des­ti­na­tion of the ca­ble, then the length and the type of the ca­ble, and then the bar­code cor­re­spond­ing to the ca­ble ID which makes it pos­si­ble to iden­ti­fy the ca­ble with a sim­ple bar­code read­er.

This is the fi­nal re­sult. The ca­bles are now ready to be con­nect­ed to the switch.