As data centre deployments become more dense in order to handle rising demand and maintain profitability, pre-planning and foresight has become essential. Alin Pirvu, technical operations manager at Voxility, explores what’s needed in order to help future-proof a data centre cabinet for the next decade.
With a growing burden of national and local regulations and standards, it’s becoming ever more challenging for the regular cloud provider to future-proof a current installation and ensure its uptime and long-term profitability.
However, there are several areas of prior study and planning that can help in this regard. One of these is the choice and configuration of the equipment cabinet in the data centre.
A suitable cabinet will need a static load rating of at least 3,000lbs. If the cabinet is being assembled elsewhere and shipped to the data centre, it will also need an equivalent dynamic load rating to ensure that it can endure the shipping process.
The cabinet will also require a rolling load rating at least equal to its static load rating, to anticipate maintenance work or internal re-organisation inside the data centre. This guarantees that it can be safely moved over short distances inside the data centre building.
A suitable seismic rating should also need to be considered, depending on the level of earthquake activity in the region of the data centre, and on local, state or national regulations relating to this. In many cases, dedicated seismic-rated cabinets can provide the quickest solution. Such enclosures feature special types of bracing and anchorage that are suitable for a data centre in an earthquake zone.
The quality and tolerance of the cabinet’s casters will have a notable influence on any of the possible load ratings discussed here. High capacity casters will increase the load-bearing potential of the cabinet by as much as a thousand pounds compared to standard caster wheels.
Though it has no influence on load capacity, the cabinet will also benefit from an integrated leveler, which can help ensure that the installation is stable and upright after an unanticipated move.
The integrity of a fully welded cabinet will usually bring a higher load rating across the board, in comparison to a flat-packed unit that is assembled on-site. However, it will be more difficult to ship, and may require more commitment to the initial design of the internals, since this extra robustness can make a welded enclosure less accessible for upgrades or on-site maintenance.
The dimensions of the cabinet itself may be dictated by standardisation within the data centre building, or other practical local considerations. Even where the data centre’s regulations permit it, pushing extra height into a limited footprint will adversely affect all of the cabinet’s load ratings.
Where possible, it may be better to either build wider or to rationalise the intended capacity into an additional unit and accept a further tier of oversight.
The cabinet’s internal space will need to exceed all the equipment that it must contain, and make at least adequate provision for maintenance access, necessary separation of different types of cabling, and allowance for the temperature management design and requirements of both the cabinet and the data centre’s own approach to cooling.
The expected heat-load from the new cabinet, combined with the cooling capacity of the data centre, will influence the location and degree of perforation in the unit’s exterior surfaces. Though it remains a controversial topic, most current server manufacturer guidelines require that at least 50% of a cabinet’s front panel be open, while conceding that more than 60% perforation will probably yield diminishing returns. Others maintain that a perforation level nearer 80% is a bare minimum.
The cabinet’s air flow design will need to accommodate either cold aisle containment (CAC) or hot aisle containment (HAC), depending on the configuration of the cabinet within the host data centre, or whether the data centre exclusively provides just one of these cooling methods. Critical air outlet routing for the cabinet should be optimised for the location of the intakes of the computer room air conditioner (CRAC).
The cabinet should be designed to accommodate blanking panels in any unoccupied areas. These, together with optimal layout of other internal components, can be used to guide the flow of hot air in the server units. This prevents recirculation and minimises the loss of cold air throughout the assembled rack unit.
The cabinet’s cable cutouts should also be designed to minimise air loss, since studies have shown that 50-80% of conditioned cold air can be lost through open cable exits.
The layout should keep power cables and PDUs away from conditioned air, since these gain no benefit from cooling and act only as an obstruction to efficient airflow. Wider cabinets should also feature vertical cable management, if possible.
In any case, good cable and pathway management is an essential feature of cabinet design. Power and network cables should be physically separate, with PDU mounting brackets and a ring cable manager cordoning off network patch cords to one side and PDUs to the other.
Finally, the cabinet should be capable of being secured from unwanted attention, in the eventuality that the host row is opened for maintenance, or for other reasons. To this end, robust lock housings on all the panels that will require access should suffice to accommodate any practical or digital securms that are chosen for the cabinet.
