Data Racks

Whether you are designing a server room, the design of the data rack is of upmost important. Configuration of the data rack should never be overlooked as it will be the basic foundation of your network design.

The data rack ensures that your I.T. equipment is organized and places your servers, switches and routers into a standardized arrangement. Since there are many options that you can choose, it is important to plan ahead as to which option best suits your needs. With proper planning, they can also improve on power protection, cooling, cable management, device management, physical security, mobility, ease of installation and protection from environmental conditions.

Data Racks and Their Functions

A data rack keeps I.T. equipment in an organized manner making use of space and other resources. Data racks consist of either two or four vertical mounting posts as a frame for stability. Typically constructed of steel or aluminum, they are designed to hold hundreds or even thousand pounds of equipment.

Rack Standards

There is a standardized spacing on standard data racks. This ensures that standard rack equipment will be compatible with standard racks. The most common standard is normally 19 inches wide, (including the mounting hardware,) and follows a standard that is set by the EIA, (Electronics Industry Alliance) and now maintained by the ECIA, (Electronic Components Industry Association.)

Rack Units

Though 19 inches in width is the industry standard, data racks can vary in height and depth, the depth being somewhat adjustable. The height of the rack is divided into rack units, or RUs which are standardized segments. Each RU is 1.75 inches high. The height of a data rack is expressed by the number of rack units followed by the letter U. As an example, a data rack that is listed as 42U contains 42 rack units. This description does not mean that this rack is exactly 42 x 1.75 inches in height. This is because there are parts of a data rack that are not useable for equipment. This description means that this rack will hold 42 rack units of equipment in any varying configuration. For instance, this rack will accommodate 42 – 1U devices, 13 – 3U devices etc.

Data Rack Types

There are three basic types of rack designs: Open Frame, Enclosed and Wall-Mounted.

  • Open Frame Racks:Open Frame Rack As the name describes, these racks are not enclosed and are composed of either two or four posts, (rails.) They are typically used where a control air flow is not needed or in an area where security is not a concern. They are a good choice for network closets or where wiring may be high-density. Typically, two post racks are designed to hold less weight than four post racks, but equipment designed for four post racks can be mounted with special equipment.

  • Closed:Closed Frame Rack As this named describes, these racks are enclosed with walls, two doors and a ceiling. These racks are also called rack cabinets. Both doors are designed for ventilation that permits air flow from front to back. Some have vents and fans on the ceiling to aid in the flow of air inside the cabinet as well. These cabinets do not provide as much room for bulk cabling, however they can be adjusted to fit most needs. Some of these cabinets also come with built in Power Distribution Units.

  • Wall-Mounted: Wall Mounted RackThese are designed to be mounted to a wall thus saving floor space and fitting in areas where other racks will not fit. They can be both either open or closed racks. Usually smaller than conventional floor racks, they cannot support the weight as the floor racks and therefore not suggested for heavy I.T. equipment.

Equipment Installed on a Data Rack

A data rack usually has I.T. equipment installed, however they can be used for other devices as well. If the data rack is for I.T. use, the equipment can be servers, switches, routers, patch panels and telecommunication devices. Other devices that can be mounted are UPS systems, KMV switches, cable managers and other production devices.

Most I.T. equipment is designed to be mounted in a standard 19-inch data rack. Some devices are smaller but have optional mounting trays or rails so they can be mounted as well.

Choosing the Correct Data Rack

There are four factors you should take into consideration when you are planning your data rack purchase: Height, Width, Depth and Load Rating.

  • Height:One of the most important consideration you should make is the height of the data rack. This is based on the determination of how many rack units are available for your equipment. Some of the most common heights for floor-standing racks and cabinets are 42U, 45U and 48U. Some customized racks can go to 58U. You should also keep in mind when considering the height of the data rack is horizontal cable management systems.
  • Width:Width of a data rack is standardized, so make sure your equipment follows the EIA 310-E standard. Standard or not, you need to consider the external width of the data rack. The standard rack is 24 inches, or 600 mm. This meets the standards for the removable floor data rack. Though extra wide racks are available, you should still take into consideration the location that you are planning to install the data rack. Enclosed, or cabinet racks usually are wider so that they can accommodate PDUs, high-density cabling and cable managers without obstructing air flow.
  • Depth:The depth of the rack is important as it should be able to accommodate your equipment while leaving space to work and air flow. Four post racks can adjust the depth to a small degree; this option is not available with the two post racks. The industry standard depth is about 42 inches, but an extra-deep 48-inch rack is available for large servers or blade chassis. This extra depth ensures enough room for cabling, PDUs, cable managers and other accessories without blocking air flow. Wall-mount cabinets are usually shallower with a usable mounting depth of around 12, 16, 20 or 32 inches.
  • Load Rating:The load rating is the amount of weight that the rack and safely support. Though this makes sense, it is important also to make sure that your floor is stable enough to support this weight as well. Floors are not the only thing you should consider. If you are using a wall-mounted cabinet, you should make sure that there is adequate wall support to take the weight of a fully loaded cabinet.

Data Rack Options

After you have decided on which rack you need, you can configure in some options. Of course, not all options are available for each type of rack. Here are some data rack options.

  • Doors: Cabinet racks, both wall-mounted and floor standing have doors. The floor standing models usually have two. The doors can be split in order to reduce clearance when opening them. Front doors can have Plexiglas® window, however this will reduce the air flow.
  • Side Panels:Side Panels: This configuration is an option. Most panels are divided into two sections to make it easier to service the enclosure. Panels without vents do improve the efficiency of the cooling by prevent hot air from recirculating through the rack and also maintain a direct front-to-rear airflow.
  • Roof:Roof: Another option that is available for floor standing enclosed racks is a roof. This roof is usually removable and includes attachment points for cable management. Some even have exhaust fans for the assistance in cooling.
  • Casters and Levelers:Casters and Levelers: When planning your data rack, you may find that you may need to move the rack a short distance during the installation process; casters are for this purpose. Once in place levelers are put into place to support the rack and equipment. These levelers can also be adjusted, as the name implies, to level the cabinet or rack if it is to sit on an uneven surface.
  • Locks:Locks: Rack enclosure doors have keyed locks. Locking the doors provide additional security for the network equipment and may be required by some industries. These keyed locks can be replaced with combination locks if so desired.
  • Hinged Wall Bracklets: Some wall mounted cabinets are hinged so that they open from the back thus giving ease of access to the equipment’s rear panels and cabling. This type of design does require more clearance and a front hinged design.
  • Mounting Holes: Threaded round holes can be typically found on two-post racks and square on four-post racks. Some four-post racks also have threaded holes as well. Some vertical mounting rails include both types.
  • Color: Most racks are black in color; however white racks are now gaining in popularity.
  • Tool-less Mounting: Keyhole slots are included on some racks. These allow you to install compatible vertical PDUs and cable managers without having to deal with screws and brackets.

Installation Planning

As with any major project, planning is essential. You must look ahead as to where your data rack will be installed and plan for an installation that will provide the least amount of unexpected roadblocks.

Room Considerations

Importantly, you must decide where your rack or cabinet is going to be installed. Is the room or closet large enough to accommodate your rack or cabinet? Can you assemble the rack or cabinet outside of this area and move it into place or are you going to have to assemble your rack or cabinet inside its final destination? Are there adequate electrical outlets capable of supplying the correct amount of voltage and amperage? What about air flow? Is there ample cooling and air circulation? Can the heat generated be removed from the room effectively? What about fire suppressant? Is one needed?

Rack Layout

The layout of the room is not only important but so is the layout and design of your rack. One important factor to consider with your rack is cooling. It is best not to mix the airflow of the equipment on the rack. In other words, do not place the equipment so that it vents hot air to both sides. Keep all of the equipment ventilating in one direction. This helps with the cold-hot air flow.

Hot - Cold Air FlowIf you have multiple racks, it is important to place them back-to-back to aid in the cold-hot air flow and so that one rack’s cool intake is not on another rack’s hot air exhaust side.

Here is an example as to how the air flow should circulate. As you can see as the hot air rises, this draws the cooler air from below to help aid in the cooling of the equipment.

Equipment Placement

You should plan in advance the placement of your equipment on the data rack. This planning will allow you to maximize the space inside the rack and permit ease of access for maintenance. This will also allow you to plan for future expansion of the rack.

Be cautious that the equipment does not exceed the rack’s load rating. Mount the heaviest equipment closest to the bottom of the rack to prevent a top-heavy rack from tipping. This is especially true if you plan on having the rack on canisters for moving. Also, do not mount slide rails too high on the rack as extending these rails will cause the rack to become top heavy and prone to tipping.

Cable management is another thing to consider when installing equipment on your rack. Some devices require high-density cabling and may cause you to need at least a 1U horizontal cable management for every 1U of patch panels or switches. Additionally, the use of any monitor should be taken into consideration. Placement should be at a comfortable height for the average user.Cable management is another thing to consider when installing equipment on your rack. Some devices require high-density cabling and may cause you to need at least a 1U horizontal cable management for every 1U of patch panels or switches. Additionally, the use of any monitor should be taken into consideration. Placement should be at a comfortable height for the average user.

Cable management is another thing to consider when installing equipment on your rack. Some devices require high-density cabling and may cause you to need at least a 1U horizontal cable management for every 1U of patch panels or switches. Additionally, the use of any monitor should be taken into consideration. Placement should be at a comfortable height for the average user.

Cooling

Because of the lower wattages of smaller equipment involved, some installations will not have any cooling issues, however most installations involve equipment that generate a considerable amount of heat and this is where cooling becomes a concern.

Airflow

Open frame racks offer no control over airflow, or at least a very minimal control. Enclosed units provide the best control of airflow. They also include several built-in features that prevent hot air from recirculating though the enclosure. It is important to keep the intake areas free of obstruction to allow the adequate flow of cool air into the enclosure.

Side Panels

The use of side panels prevents hot air from circulating around the sides of the enclosure. Though in theory a good idea, ventilated side panels actually encourage the recirculation of hot air around the equipment.

Blanking Panels

Blanking panels aid in directing the cold air through your equipment and prevents the hot air from recirculating. These panels work well for enclosures but provide little airflow management with open racks.

Cable Management

Cables left unmanaged not only look unsightly and unprofessional, they also cause issues when trying to troubleshoot network issues. Additionally, unmanaged cable placement also interferes with the airflow necessary for the cooling of your data rack equipment.

Enclosures use horizontal and vertical cable managers in which to organize patch panel cables and power cords. Consider an extra-wide enclosure if you plan to install equipment that requires high density cabling.

Thermal Ducts

You can aid with the hot air removal with the use of overhead thermal ducts. These ducts act as a chimney to route the hot air away from the equipment. This hot air can be routed directly to the plenum or HVAC/CRAC systems for disposal thus preventing it from interfering with the cold air intake.

Active Heat Removal

Ventilation fans aid in the removal of heated air. Fans can be added to the top of an enclosure and can be used for both floor standing and wall-mounted enclosures.

Close-Coupled Cooling

Closed-coupled cooling provides exact air conditioning that works well with data rack equipment. They also provide better efficiency than the traditional perimeter or raided floor systems. These systems can moderate hot spots without the need to lower the entire room’s temperature. Due to their modular design, these systems can be configured quickly to handle overheating racks. They are self-contained and can be installed by I.T. staff without outside help thus reducing costs.

Accessories And Options

There are other accessories and options that you may want to consider for your data rack.

  • Power Distribution: Make sure you have adequate power outlets that can handle the wattage and amperage required to run your data rack equipment. Power distribution, (PDU) systems will aid in reaching areas where outlets are not as nearly placed as needed. These devices also have other options such as current monitoring and remote management.
  • Battery Backup Sytems: The reliability of the power going to your equipment needs to be assured. Receiving good power all the time from your electrical company is not always dependable and using a battery backup system will provide reliable voltage. These UPS’s can come in rack mount or floor units and can condition the power going to your equipment. Most systems will sound an alarm allowing you to safely shut equipment down should total power be lost.
  • Device Management: Controlling multiple devices from a single location can easily be accomplished with the use of a KVM switch, a single monitor, keyboard and mouse. These devices usually only take up 1U of space.
  • Patch Panels: Patch panels provide space savings, high density cable connections. They also aid in lowering maintenance costs and aid in installation and configuration errors.
  • Environmental Monitoring: Environmental sensors aid in the reporting of temperature variations in the room and work remotely through networked UPS systems and PDUs. They can time stamp and record temperature variances as well. This works well as some heat related issues may only occur when equipment is under heavy usage and can help you pinpoint trouble areas.
  • Security: Security does not end with the locking of the cabinet doors, it extends further. Accessories can provide additional security along with monitoring. Some examples of these monitoring features included magnetic intrusion detection switches.
  • Shock Pallet: A shock pallet is a reinforced shipping pallet that allows you to install equipment in an enclosure at one location then ship it to a final installation location with the equipment inside and installed.
  • Knockdown: Floor standing cabinets, which usually ship assembled and ready for installation may not be able to be rolled into place due to restricting sizes of doorways, stairwells or elevators. Sometimes the cost is a factor preventing the shipment of pre-installed cabinets. In either case, enclosures can be shipped flat in partially assembled sections that provide the required compactness without making assembly difficult or too time consuming.
  • Stability: Most floor standing racks and cabinets can be bolted to the floor thus providing extra stability and preventing the racks from tipping over. Another way to facilitate stability is to bay enclosures and racks together.
  • Enviromental Protection: Hopefully, your I.T. install will be in a clean area, but this is not always the case. Sometimes installs will be in areas such as factory floors or warehouses where the conditions can be less than clean. There are enclosures that are NEMA, (National Electrical Manufactures Association) rated. These cabinets are sealed and provide a filtered airflow to protect equipment against environmental hazards. One option is to assemble the equipment in a clean location and transport it to the unclean location. Some NEMA rated enclosures also provide seismic protection as well.
  • Seismic Protection: Seismic rated enclosures are constructed to withstand vibrations both internal and external, including earthquakes. These enclosures include heavy duty torsion resistant construction. They are tested by subjecting them to a series of standardized tests that indicate the degree of violent motion they can withstand.

Custom Rack Designs

If you cannot find exactly what you need in an "off the shelf" data rack, (and chances are you won't,) you can have a data rack custom built to your specifications. A full service manufacturer will be able to technical specs, cost, facility and personnel. Custom designs can be affordable, however there may be a minimum build requirement and some lead time to complete and ship. This will all be based on the type and degree of your customization.

Regarding the lead time on a custom build, you should plan this into your project. The lead time is the time required for the order to be delivered, the setup the manufacturer needs to gather all of the required hardware, build time and delivery time. Add to this any other manufacturing time including special tooling. Without planning for this lead time, your project could experience significate delays.