This website uses cookies primarily for visitor analytics. Certain pages will ask you to fill in contact details to receive additional information. On these pages you have the option of having the site log your details for future visits. Indicating you want the site to remember your details will place a cookie on your device. To view our full cookie policy, please click here. You can also view it at any time by going to our Contact Us page.


Cabinets and racks are now critical data centre elements

Not so long ago, the 19in cabinet that is found in virtually every data centre was a relatively straightforward piece of steel that simply housed equipment.

But not any more. Today’s data centre cabinets play a key role in achieving critical requirements such as cooling, equipment density, monitoring and security. It means making the right choice of cabinet has become extremely important.

Today, cabinets and the racks they contain are far more than containers and they play a highly significant role in the successful performance of the modern data centre.

This has largely happened because of the huge increase in demand for online information and transactional services. From an era when most information was text, we have reached the point where streamed video, increasingly high definition, is needed for almost everything from websites to on-demand TV and video telephony. The latest drivers of this revolution are ubiquitous mobile devices like tablet computers and the iPhone and its competitors.

Developments like this have massively increased the need for data storage, greater bandwidth, and processing capability. This has not only led to the building of new data centres, but also forced companies to pack the maximum possible amount of equipment into their existing physical spaces.

In practice, this has led to the once standard multi-U servers being replaced by 1U pizza-box servers, now the norm. But already, these are being replaced by power hungry blade servers, which can provide an effective density of many servers per U. A ‘U’ is the height increment between the pairs of mounting holes in a cabinet and typically there are 42 to 52 ‘U’ per cabinet.

Underlying these moves is of course the bottom line, with the key aims being minimising capital and operating expenditure and maximising return on investment, revenues and growth. But equally, companies want to eliminate unpredictability while also lowering energy consumption and minimising their carbon footprint.

Power dissipation
Probably the most significant development for data centres as a whole and their cabinets and racks concerns power. A decade or more ago, power dissipation was so low that nothing special was required, with ordinary convection being sufficient to remove the heat from the rack.

Now, the process of packing the maximum possible processing capability and storage into the available space has hugely increased heat density, which is estimated to have risen from less than 1kW per rack to an average of 2-5kW, with high end equipment reaching 20kW or even 30kW.

This scenario has led to a range of methods being used to remove the heat from individual cabinets, and also in the overall management of the heat generated by the entire data centre. As a result, data centre planners generally need expert help in this area.

For the individual cabinet, heat is typically extracted by front-to-back airflow, through mesh doors. Cooled air from the computer room air cooling (CRAC) units is fed into the cold aisle and then out into the hot aisle. From there, hot air eventually travels back to the CRAC units for further cooling. If heat density in a rack rises above a certain point, it can become necessary to add fans to the rack’s rear door in order to pull hot air out, and hence pull cold air in, more quickly.

Even so, the heat generated often means that this technique is inadequate, frequently when the racks in a row average around 5kW. Then, hot air from the rear reaches the cold aisle, and starts to warm the cold air before it gets the chance to enter the cabinets.

When this happens, the whole cooling scenario gets more complicated. It calls for more sophisticated processes to prevent this, such as an arrangement called aisle cocooning. As heat density goes on rising, it may be necessary to implement ‘close coupled’ cooling, in which cooling units are mounted directly inside the cocoon, either between cabinets in the row or even within cabinets.

Inside the cabinet, it is vital to control airflow so that back-to-front (hot side to cold side) airflows are eliminated. This kind of air-feedback can seriously degrade cooling performance, resulting in equipment reaching dangerously high temperatures within the rack, causing the risk of devices failing and subsequent downtime.

That is why it is so important to install cabinets in which cooling can be easily upgraded to more powerful options throughout a data centre’s lifetime. Such a strategy can prevent serious disruption in the future, as the constant need for greater performance inevitably leads to more heat being generated in a particular space.

For example, equipment is already available that takes power dissipation to 30kW per cabinet. Even though there are cooling solutions in production that can achieve up to 60kW per cabinet, they will soon be widely used, and the industry will need to create even more powerful cooling solutions.

Access control
Another problem for data centre managers is controlling access to the extremely important, and expensive, equipment that they contain. Whether the data centre is a single operator location, such as a corporate data centre, or a multi-operator like a co-location data centre, lots of people may need access to each cabinet. Inevitably, not everyone is as careful as they should be, and in some cases damage may even be deliberate.

Whatever the cause, the results of interference and potential damage to key IT equipment can be hugely significant, as companies such as Vodafone and Blackberry can confirm. This, combined with other requirements, like data protection measures, Sarbanes Oxley, BASEL II and PCI for auditable records of physical and electronic access, has turned ‘active security’ into an essential aspect of many data centres.

What that means is that the simple security processes of yesterday such as passive key operated cabinet locks, or even code operated, are not good enough anymore. Now, locks must be software controlled, with code, iris or thumbprint recognition required. Nor is it just a matter of controlling who can access the cabinet. It can be just as important to restrict the access time allowed, with alarms generated if unauthorised access is attempted, or when a cabinet is left open beyond an individual’s specified time slot.

Thus, today’s cabinet security systems can be backed up by CCTV cameras that record the access operation. Also, it is possible to specify that two people, such as the technician and a security overseer, must authenticate the system before the cabinet can be unlocked. And as a further back-up, a complete audit trail, containing video if recorded, can be retained for any possible investigation.

A 19in standard?
In the world of data centres, the 19in equipment practice may be a standard, but in practice the actual equipment described as 19in is far from standard. Often, companies want to use equipment from a range of suppliers, and it turns out that not every vendor’s equipment will actually fit into every 19in cabinet.

The answer to this problem is to use cabinets that have been designed specifically to offer adjustability, so that they can accommodate the features of the equipment being installed. Also, it is vital that a cabinet maintains the highest levels of back-to-front airflow isolation, even if the equipment installed in it features many different sizes and shapes. This is yet another reason to beware of simple, cheap cabinets.

Temperature monitoring
Given the problems posed by ever increasing heat generation, monitoring temperatures inside cabinets sounds like an obviously good idea, yet for a long time it stayed like that – just an idea. But times have changed, and today it really is vital at multiple points on the cabinet.

Today’s server-grade processors consume such a level of power that if the cooling becomes inadequate, temperatures will accelerate rapidly and vital chips will die, causing downtime. Even if immediate failure does not occur, regular rises in temperature can seriously shorten the life expectancy of many devices, making potential downtime more likely.

Temperature monitoring is not just a matter of looking at the whole cabinet, it is vital to check it on a per-equipment basis. That is because it makes it possible to find hotspots and do something about them before they become serious, as well as enabling users to install new equipment and know they are not inadvertently creating hotspots. Other benefits include ensuring that a cabinet’s power supplies are not overloaded, and detecting abnormal power loads that could be the sign of equipment developing a fault, thus avoiding future failure.

Controlling cabinets
A modern data centre is absolutely dependent on the sophistication of the cabinet/rack and the extended infrastructure attached to it. Compared with the past, it represents a huge increase in functional capability. As a result, the task of managing such advanced elements – which could number hundreds or even thousands of cabinets – becomes a major challenge in itself.

The result is that it demands a dedicated tool, such as Cannon’s DCM data centre management software, that can handle all of the inputs and outputs, operating local alarms and controls, and integrating all of these into a data centre’s main network operations centre software platform.

Software control is now a key aspect of the use of data centre cabinets, and this brings with it a series of other benefits, such as the ability to carry out capacity planning, perform ‘what-if’ modelling, and conduct task-management to optimise the deployment of a data centre’s most important resource; its people.

We have travelled a long way from the days when a data centre cabinet was not much more than a piece of steel. Today, it is a complex sub-system with a major influence on the performance and efficiency of a data centre, affecting everything from cooling efficiency and power consumption, to future development and flexibility, its data capacity, and even the centre’s whole financial performance.

Matt Goulding is Managing Director of Cannon Technologies

Contact Details and Archive...

Related Articles...

Print this page | E-mail this page

Electrical Products