The concept of Murphy’s Law – “anything that can go wrong will go wrong” – is essential to consider in data center planning.  Data center managers should assume that Murphy’s Law is true and plan for redundancy and the possibility of an outage. An outage can cause downtime…and nobody has time for that.

We wanted to recap some of the “best” data center articles from the past couple months, so you can get your fix all in one place. Make sure to check back each month for the latest recaps and other fun and informative posts!

Outages can be caused by any number of events such as fire, network glitches, human error, major disasters and equipment failure. Here are a few of the articles that caught our attention:

• County Offline after Data Center Fire (no backup data center)

• Network Glitch

• Human Error – can cause as much as 75% of downtime!

• Cut Cable

• Superstorm Sandy

The real issue is not whether data centers will go out or how long they will stay dark, but rather how prepared you are to deal with it.

We suggest following a structured cabling system and planning for redundancy. The TIA-942 standard includes guidelines for data center design and installation of a data center (including physical spaces and structured cabling infrastructure).

Follow the TIA-942 best practices and build a structured cabling system with no single points of failure for power, cooling or data connectivity.

CABLExpress Skinny-Trunk Harness

Choosing the cables for your network infrastructure is one of the most critical, yet often overlooked, choices made by an IT professional. Many view the choice of fiber cables as an afterthought to hardware purchases.  Also, a choice made is often mistakenly based on a simple cost decision using very basic criteria for the purchase – for example, “it needs to have LC connectors and an aqua jacket.” This is an uneducated purchase and all too often leads to catastrophic failure somewhere in the network, which ends up costing the purchasing entity much more than the initial dollars saved.

The following are important criteria for choosing fiber cables for a network infrastructure and the reasons why they are important.
This will allow you to make educated decisions on your purchases.

Low dB Loss Ratings

Choose a fiber cable assembly that has low dB loss ratings. The higher the dB loss, the more likely this fiber cable assembly will cause errors in the network. It is all about signal strength! The better the signal strength, the less chance there is for network errors. Fiber cables with low dB loss offer a better signal strength between transceivers and, therefore, have less chance of network errors, troubleshooting issues and potentially DOWNTIME! Look for a maximum dB loss (sometimes referred to as insertion loss) of 0.15dB for LC connectors and 0.25dB for MTP® or MPO style connectors.

Repeatability

Repeatability is important in choosing fiber cables. Inferior components and termination techniques can be used by manufacturers to reduce manufacturing costs. The result can be a fiber cable that looks identical to another, but has a much higher potential for failure after repeated plug-ins. This is a very dangerous and very frustrating problem because the fiber cable was working, then it is not – so it is often the last thing to be checked!  Ask your provider(s) for documentation on their repeatability testing and information on the components they are using. Quality manufacturers will be constantly testing their assemblies to ensure they work the same on the first plug-in as well as the 500th.

Manageability

Manageability is often overlooked when purchasing fiber optic cables. Thicker jackets can lead to cable congestion, which leads to potential equipment cooling issues. Not to mention it also just looks bad! Pay attention to overall design when choosing fiber cables and request samples to evaluate the manageability. Also, keep in mind that fiber cables are typically used in higher counts. When evaluating two products next to each other, a smaller diameter may seem insignificant; however, when there are 144 of these bundles together the difference is visibly more dramatic!

Paying attention to these key points can help you distinguish “cost” from “overall value.” To reiterate, if you save a few hundred dollars when just evaluating with raw cost, you could end up costing your organization thousands of dollars in troubleshooting man hours – and even more for a catastrophic failure. If you choose wisely you can spend only a little bit more while significantly reducing troubleshooting time and virtually eliminating downtime threats due to cabling malfunction. Also, know that you need not pay huge premiums for quality fiber cables. Do some research and contact multiple suppliers and manufacturers, as there are some high performance fiber cable assemblies to be purchased without paying a premium price!

The most basic ways to protect your fiber and maintain maximum performance are to:

• Minimize end-face contamination
• Avoid excessive bending

We have outlined simple ways to approach both of these steps below.

Minimize End-Face Contamination

Don’t assume that just because a cable hasn’t been used that there is no risk of contamination. There is always the possibility that condensation has formed during shipping. Contamination (from dust particles, food particles, lint, skin oil, condensation) will increase insertion loss and could lead to downtime.

Remember to clean end faces prior to mating. Contamination, like the common cold, can be transmitted when mating connectors. Minimize risks by following the “Inspect, Clean, Inspect” routine EVERY TIME and repeat, if necessary!

For more information on how to inspect and clean your end faces, check out our Cable Talk videos #4 and #23.

More than 50% of network outages
are due to end-face contamination!

Avoid Excessive Bending

Excessive bending can cause light losses due to micro and macro bends. Bend Insensitive Fiber, commonly called BIF,  is a major improvement and helps to reduce the losses.

The bend radius is the minimum radius you can safely bend the cable without a loss occurring. The rule of thumb for the bend radius, the typical cable manufacturer standard (with the use of BIF), is that it is 10 times the diameter of the outer jacket of the cable.

Bend Radius Formula:  Cable Diameter x 10

• For instance, if you have a 2 mm fiber cable x 10 = 20 mm (bend radius) or 0.79 inches.

• Now, this bend radius works for how you would typically place your cables in a structured cabling system, but sometimes it’s easier to visualize the diameter. If you’re looking to calculate the bend diameter, simply multiply the bend radius by 2. In this case, the bend diameter is 40 mm or 1.6 inches.

It may help to envision an everyday object, like a paper towel tube – this is the amount of bend allowed with BIF fiber.

Prior to BIF, bend losses were much higher. The minimum radius specified was typically not less than 15 times the cable diameter. This means that the fiber cable could only safely bend around the size of a sports drink bottle, almost 2.5 inches!

Check out Cable Talk video #32 for more info on the bend radius of BIF.

By following these two simple guidelines – minimizing your end-face contamination and avoiding excessive bending – you will be able to properly maintain your fiber cabling, thus allowing for maximum uptime in your data center.

With so many terms floating around regarding data center technologies, we wanted to take a moment to simply explain an emerging trend that many IT pros may be in the process of implementing – FCoE.

As you may know, FCoE stands for Fibre Channel over Ethernet. A network technology used in data centers, FCoE essentially merges the Fibre Channel protocol with the Ethernet protocol.

FCoE is a great solution to many of the problems that are faced in the data center today, the biggest being that there is one “language” for storage area networks and another “language” for the network. Having these two different languages leads to massive cable sprawl, exponential port growth and cable management issues.

FCoE takes Fibre Channel frames and encapsulates them into an Ethernet network. It is not a standard Ethernet, though -  it is an improved version of Ethernet that provides low latency and high quality of service. It is kind of a “best of both worlds” scenario. Due to this, FCoE will offer higher bandwidth options than traditional Fibre Channel.

Image via NetworkWorld

Major manufacturers, such as Cisco and Brocade, are currently offering products that utilize FCoE. This technology could benefit many data center designs by reducing the amount of equipment and infrastructure needed. However, this does stress the importance of having a fiber cabling infrastructure that can handle the speeds and bandwidth needed in order to do so. Low loss, scalable and modular cabling systems will allow enterprises to maintain maximum uptime and minimize disruptions when running FCoE.

Okay, so you’re tasked with finding a cabling vendor for your SAN fiber. What do you need to know to make an educated decision?  We know that performance, reliability and manageability are all important. But what are the questions that you need to ask to ensure that your requirements are met?

What standards do you follow? Do you recommend structured cabling or point-to-point. What is your maximum dB loss?  Can you help me with loss budgets?

We know that there are many ways to do things, but this is our advice based on extensive industry experience. Here at CABLExpress we follow the TIA-942 Structured Cabling Standard. We recommend the use of a Main Distribution Area (MDA) and a structured cabling system. This organized system will future-proof your data center for generations of hardware to come and you will greatly reduce the problems of cabling congestion and cooling found with a point-to-point spaghetti cabling mess.

Additionally, we recommend using an MTP solution, which will ensure you are ready for the moves to 40 and 100Gig speeds.

Perhaps most importantly, you can’t afford downtime!  Our maximum dB loss at 0.25 per MTP well exceeds the industry standard. Note that this is maximum, not just typical! Most SAN fiber systems will need to be under 1.5dB to obtain the required distances.

If you have any questions about the proper way to implement your SAN fiber, our experienced staff can help you with this. We have data center architects, RCDD and infrastructure specialists all available to answer your questions – we’d love to talk with you!

If you want to learn more about structured cabling, check out this FREE white paper: