Black Box Network Services : 2011 : April

Beat the heat: efficient cooling in the data center

Posted by diane.magin@blackbox.com Apr 26, 2011

Cooling in the data center can be a lot like a black money hole, in that it’s a big energy sucker. How can you keep it cool and balance your budget by using efficient cooling technology? We know that the growing demand for power is a challenge, so choosing the best system for your data center is important.

Fortunately, there are a number of cooling methods to choose from, whether you are building a new data center or retrofitting one. And emerging green technologies offer exciting possibilities for advances in efficiency and cost savings.

Whether under the floor, above the floor, in the rack, or above the rack, the requirement of data center cooling remains the same: Warm air must be moved away from equipment and cool air towards it. Understanding the factors that can hinder or even prevent this from happening is one of the first steps to improving data center efficiency.

Air conditioners and air handlers
The familiar air conditioner (AC) unit, installed in the data center and connected to outside condensing units, uses a fan system to move cool and hot air where they need to be. It’s much like the systems used in residential settings except that, in building, cooling, the evaporator coil and blower are separate from the condenser coil, compressor, and condenser blower, while in electronics cooling they are packaged together in one unit.

Computer room air handlers (CRAH) work much the same way except that they use chilled water instead of refrigerant to remove heat from the air.

You might think that the drier the data center, the better. But, in fact, the American Society of Heating, Refrigerating, and Air-Conditioning Engineers (ASHRAE) has a recommended range of humidity levels to help ensure longevity.

Hot aisle/cold aisle
The idea of hot aisle/cold aisle seems simple, but it’s a little tricky. Ideally, cool air passes in front of parallel rows of racks, being drawn in toward equipment, and hot air comes out the back of the rack or overhead and is exhausted out of the room, producing constant air circulation.

Most major server manufacturers recommend that cabinet doors used in hot aisle/cold aisle installations have at least 63% open area for airflow. You can achieve this by either removing cabinet doors altogether or by buying cabinets that have mesh doors. Also, cabinets with side panels keep the air within each cabinet from mixing with hot air from an adjacent cabinet.

Because most servers and other network devices are equipped with internal fans, open or mesh doors may be the only ventilation you need as long as your data center has enough air-conditioning to dissipate the heat load.

Here’s where the tricky part comes in. Cool air can escape through various holes like cable cutouts, and some hot air doesn’t get exhausted and may enter the cold aisle, resulting in inefficient air handling and the presence of hot spots. These problems can be overcome through various analyses and equipment modifications.

Blanking panels, for example, can prevent cold air from passing through a cabinet too quickly or in the wrong direction and are a simple and economical way to direct cold air through equipment and prevent it from mixing with hot air. Brush strips, although not airtight, can cut down on air leakage while keeping dust and other contaminants out of cabinets.

You can increase ventilation by installing fans to actively circulate air through cabinets. The most common cabinet fans are top-mounted fan panels that pull air from the bottom of the cabinet or through the doors. Or you can use a fan or fan panel that mounts inside the cabinet or choose cabinet doors with built-in fans. For very tightly packed cabinets, an enclosure blower is a specialized high-speed fan that mounts in the bottom of the cabinet to pull cool air from a raised floor across the front of the cabinet where it can be used by equipment. An enclosure blower requires a solid front door with adequate space—usually at least four inches—between the front of your equipment and the cabinet door for air movement. If you’re housing components outside of a temperature-controlled area, you may want a cabinet with its own air conditioner.

Hot aisle/cold aisle containment
In hot aisle/cold aisle containment, barriers are used to enclose the aisles, ensuring cold air and hot air stay where they should be to maximize AC efficiency. Cold air stays near the server intake, and hot air exhaust is shuttled to in-row air conditioners, conditioned, and then returned to the cold aisle.

To keep cool air from mixing with arm air, row ends are closed off with an airflow barrier. This barrier can range from makeshift arrangements of plastic strips to doors made specifically for this purpose.

Because cold aisle containment concentrates cool air at the front of equipment where it’s most needed, it’s a great cooling method. Cold aisle containment significantly reduces energy costs, lowering power bills as well as reducing data centers’ carbon footprints.

http://bboxblog.files.wordpress.com/2011/04/hotaisle-coldaisle.jpg

Liquid cooling
Liquid cooling systems are air conditioners that use a liquid to dissipate heat. That may be cold water or refrigerant, but the difference is that the liquid is closer to the heat source, resulting in even more efficient cooling.

Green cooling
The world of data center cooling is evolving alongside “green” or sustainable technologies, as data center managers contend with power, cooling, and space limitations.

Servers designed to handle higher temperatures are an example of so-called “adaptive” cooling. “Free” cooling, on the other hand, is almost like simply opening a data center window, except the windows are filters and louvers for cleanliness and air control. In the right environment, methods such as these can save tremendous amounts of money and energy.

Geothermal cooling is an example of a more involved green system. In traditional chilled water system, a majority of the water can be lost to evaporation. With geothermal cooling, evaporation can be cut to zero.

Power demands generally vary throughout the day, and system with variably frequency drives can adjust the power as needed.

Chill out!
These and other evolving technologies may drastically change the way data centers are cooled in the future. Choosing the right cooling system saves money and protects your investment. How do you keep your data center cool? What advice would you offer to others looking to build or retrofit their data center?

Data center resources:
Quiet Fan Panels: Equipment cooling without the noise (PDF)
Video: How to pick a cabinet
White Paper: Extending the Life of Your Data Center

162 Views 0 Comments Permalink Tags: cooling, heating, racks, cabinet, black_box, data_center, liquid_cooling

Win the Reseller Battle - Weapon #5

Posted by diane.magin@blackbox.com Apr 12, 2011

Here's the fifth weapon in your 10-part reseller arsenal:

The right tools to make your job easier. It's easy to do business with Black Box. We understand your business. Like us, you work hard every day taking care of your customers. That's why Black Box provides the right tools to make your job easier:

Technical expertise: An extension of your business

When you call black Box Tech Support or click Talk to an Expert, you'll be speaking with one of our technology experts in 30 seconds or less. Our in-house experts are here 24/7 to answer your questions—before, during, or after the sale. What's more, their advice is FREE!

Click Talk to an Expert now and bookmark the page for immediate support.

No-questions-asked returns

Although we hope you never have to return a product that you have sold to a customer, returns are easy at Black Box. We offer a no-risk, 45-day return policy from the invoice date. There is also no restocking fee for Black Box products returned in new condition and in the original packaging.

Rapid quote turnaround

When time counts—and it always does—rely on Black Box to get you the quotes you need for your customers quickly. It’s one of the things we’re known for, and it’s another way we help make your job easier.

Exceed your sales plan by using all the reseller weapons. If you missed Weapons #1–4, click here.

Call or e-mail now! Let Black Box’s arsenal of tools, people, and technologies help you win the reseller battle.

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Beware of the microchip: TEMPEST and Common Criteria

Posted by diane.magin@blackbox.com Apr 12, 2011

It should come as no surprise that the federal government is concerned about signal leakage. In fact, its interest goes back to the days of World War II when the Army was trying to exploit weaknesses of enemy combat phones and radio transmitters. Since then, the scope of the government’s interest has broadened beyond the battlefield. In the last 40 years, the National Security Agency (NSA) has taken several industry measurement standards for signal protection and greatly enhanced them.

These enhanced criteria are commonly referred to as the TEMPEST standards (although the NSA also calls them EMSEC standards, short for “emissions security”). TEMPEST pertains to technical security countermeasures, standards, and instrumentation that prevent or minimize the exploitation of vulnerable data communications equipment by technical surveillance (AKA eavesdropping!). It involves designing circuits to minimize emanations. Another set of testing standards is called Common Criteria (EAL4+). Both standards are important, but they test for different things.

TEMPEST

Many things put your data communications at risk. Any device with a microchip generates an electromagnetic field, often called a “compromising emanation” by security experts. With the proper surveillance equipment, these emanations can be intercepted and the signal reconstructed and analyzed. Unprotected equipment can, in fact, emit a signal into the air like a radio station—and nobody wants to risk his or her job and a whole lot more by broadcasting national security or trade secrets to the wrong people.

Some of the most vulnerable equipment includes speakerphones, printers, fax machines, scanners, external disc drives, and other high-speed, high-bandwidth peripherals. And if the snoop is using a high-quality interception devices, your equipment’s signals can be acquired up to several hundred feet away.

TEMPEST testing, while classified, is regarded as a process that assesses the threat of data linking by various covert electromagnetic eavesdropping mechanisms. TEMPEST testing and certification is often required by military organizations, and ensures that equipment is designed to minimize emanation.

The TEMPEST standards require red/black separation. In military and government IT setups, that is the most common segregation between secure and non-secure networks. “Red” circuits are normal, unsecured circuits and equipment. Separation is ensured by maintaining physical distance or installing shielding between “red” and “black” circuits and equipment.

TEMPEST is vital for areas where physical security is either not possible or limited. When equipment is on a vehicle or deployed in an active zone, use of TEMPEST-rated equipment is a must when sensitive data is involved. It can be a user’s only line of protection.

Common Criteria (EAL4+)

Common Criteria is an international standardized process for information technology security evaluation, validation, and certification. The Common Criteria scheme is supported by the National Security Agency through the National Information Assurance Program (NIAP).

Common Criteria defines a common set of tests regarding the process of design, testing, verification, and shipping of new security products. Common Criteria enables customers to assess a level of trust in how a product has been designed, tested, built, and shipped.

When shopping, be sure to get secure KVM switching for networks with multiple security classifications. For more information, visit the Secure KVM section of blackbox.com.

302 Views 0 Comments Permalink Tags: networking, black_box, kvm, network_security, kvm_switch, tempest, common_criteria

Certify fiber optic cable like a champ

Posted by diane.magin@blackbox.com Apr 3, 2011

If you’re accustomed to certifying copper cable, you’ll be pleasantly surprised at how easy it is to certify fiber optic cable because it’s immune to electrical interference. You only need to check a few measurements.

Attenuation (or decibel loss)—Measured in decibels/kilometer (dB/km), this is the decrease of signal strength as it travels through the fiber cable. Generally, attenuation problems are more common on multimode fiber optic cables.

Return loss—This is the amount of light reflected from the far end of the cable back to the source. The lower the number, the better. For example, a reading of -60 decibels is better than -20 decibels. Like attenuation, return loss is usually greater with multimode cable.

Graded refractive index—This measures how the light is sent down the fiber. This is commonly measured at wavelengths of 850 and 1300 nanometers. Compared to other operating frequencies, these two ranges yield the lowest intrinsic power loss (NOTE: This is valid for multimode fiber only.)

Propagation delay—This is the time it takes a signal to travel from one point to another over a transmission channel.

Optical time-domain reflectometry (OTDR)—This enables you to isolate cable faults by transmitting high-frequency pulses onto a cable and examining their reflections along the cable. With OTDR, you can also determine the length of a fiber optic cable because the OTDR value includes the distance the optic signal travels.

There are many fiber testers on the market today. Basic fiber optic testers function by shining a light down on end of the cable. At the other end, there’s a receiver calibrated to the strength of the light source. With this test, you can measure how much light is going to the other end of the cable. Generally these testers give you the results in dB lost, which you can then compare to the loss budget. If the measured loss is less than the number calculated by your loss budget, you installation is good.

Newer fiber optic testers have an even broader range of capabilities. They can test both 850- and 1300-nanometer signals at the same time and can even check your cable for compliance with specific standards.

Precautions to take when using fiber

Intrinsic power loss—As the optic signal travels through the fiber core, the signal inevitably loses some speed through absorption, reflection, and scattering. This problem is easy to manage by making sure your splices are good and your connections are clean.

Microbending—These are minute deviations in fiber caused by excessive bends, pinches, and kinks. Using cable with reinforcing fibers and other special manufacturing techniques minimizes this problem.

Connector loss—This occurs when two fiber segments are misaligned. This problem is commonly caused by poor splicing. Scratches and dirt introduced during the splicing process can also cause connector loss.

Coupling loss—Similar to connector loss, coupling loss results in reduced signal power and is from poorly terminated connector couplings. Remember to be careful and use common sense when installing fiber cable. Use clean components. Keep dirt and dust to a minimum. Don’t pull the cable excessively or bend it too sharply around corners.

These properties particular to fiber optic cable can cause problems if you aren’t careful during installation.

For more cabling tips visit our resources page.

302 Views 0 Comments Permalink Tags: cable, black_box, cabling, fiber_optic_cable, copper_cable, certify