A Guide to Data Centre Wireless Environmental Monitoring Systems

Whether you need to monitor a data centre’s environment for power, cooling or security, new wireless monitoring solutions offer a range of cost, data acquisition and management benefits that could just swing the balance the next time you need to gather environmental monitoring data to manage your critical data centre infrastructure.

What is Wireless Data Centre Environmental Monitoring?

Traditional environmental monitoring devices have at least one Ethernet RJ45 port to connect them via an RJ45 cable to a local IP network. Once connected the environmental monitoring device can report data from plugged in sensors for temperature, humidity, water leakage and a range of environment related information to an environmental monitoring software platform.

Wireless connectivity removes the need for the RJ45 cable. Whilst an environmental monitoring device may still have an RJ45 port, communication and control is ‘wireless’. A wireless monitoring device may be powered from a local mains power supply (via an AC/DC adaptor) and/or a built-in lithium-ion battery.

In a server room or data centre environment, wireless environmental monitoring can solve several installation and management issues and will reduce the overall cost per monitored device. For the same operational budget, a larger number of low power wireless environmental sensors can be deployed over a larger area of the data centre facility and the data centre environmental monitoring system can be more easily extended over time.

For more information on wireless data centre monitoring see:
https://ieeexplore.ieee.org/document/6740348

Wireless Technologies for Data Centres

There are several wireless technologies that could be used in IT, server room and data centre type applications, with each defined by their transmission speed, range, and data packet size:

• Wi-Fi: the most used wireless technology is Wi-Fi. It is the one we use on public and private networks with smart phones, tablets, and laptops to easily connect to a local area network (LAN) and the internet. Wi-Fi is an abbreviation for ‘Wireless Fidelity’ and the term can also be used to refer to wireless local area networks or WLANs. Wi-Fi is an extremely popular wireless technology because of its high data rate but it has too drawbacks when it comes to use in wireless server room and data centre applications. The first is that it is power-hungry and the greater the size of the data pipe and volumes of the data transmitted, the greater the power draw. This means that Wi-Fi routers and devices need to be powered from an AC source of use Power-over-Ethernet (PoE). They are not suitable for battery-powered wireless environmental monitoring solutions and wireless sensors.
• Zigbee: is a ‘wireless mesh network’ made up of radio nodes/devices organised into a mesh topology to form a wireless network. The term ‘mesh’ refers to the rich interconnection between the nodes/devices. A wireless mesh network consists of mesh clients, routers, and gateways. Zigbee is an IEEE 802.15.4-based specification for a suite of high-level communication protocols. Zigbee is suitable for small, lower-power devices in applications such as home automation. It has a short range of only 10-20m and the signal can be affected by multipath distortions in a server room or data centre application by for example metal server racks cabinets and other large metal-clad devices such as uninterruptible power supplies (UPS) and computer room air conditioners (CRACs).
• LoRa: is a proprietary low-power, wide-area network modulation radio technology. The term ‘LoRa’ stands for ‘Long Range’. LoRa can be used to cover distances from 5-15km (city to suburban areas) and within buildings it has a better ability to penetrate walls and barriers compared to other wireless technologies including Wi-Fi, Bluetooth and Zigbee. LoRa uses the chirp spread spectrum and broadcasts on unlicensed bands including 833MHz in Europe, 915MHz in North America, and 923MHz in Asia. However, LoRa is not suited to real time data acquisition as required in server room and data centre monitoring applications. LoRa has a low-data transmission rate (up to 27kps) and low network duty cycle, meaning that small packets of data can only be sent every few minutes.
• Wireless Tunnel Gateways: this is a proprietary protocol from AKCP that uses LoRa Radio technology as the physical layer. The AKCP Wireless Tunnel Gateway combines the Lora advantages of long transmission range and low power consumption and combines these with the ability to send larger packets of data at a greater speed to provide a solution for real time data collection and environmental monitoring.

Whilst going wireless has two primary advantages. There are concerns within server rooms and data centre applications when it comes to wireless networks. However, the Wireless Tunnel Gateway technology from AKCP overcomes these.

The Benefits of Wireless Data Centre Monitoring

• Speed of Deployment: with a wireless environmental monitoring system, sensors can be deployed far faster than with a fixed-wire system and at a much lower cost. A wired installation within a medium-to-large data centre installation may require several hundred meters of expensive network cabling, together with connection points and patch panels that will take up valuable rack space. Wireless sensors can also be moved quickly and efficiently without the need to update cabling and layout plans.
• Lower Cost of Deployment: when it comes to operational costs, these can also be dramatically reduced when compared on a cost-per-port basis and the time required to make new installations or reconfigure existing ones.
• Reliability: when correctly deployed wireless technologies can achieve higher reliability than fixed-wire connections. In a fixed-wire installation there is a greater chance of an accidental cable disconnection or a poor cable termination. Wireless connectivity can also be more reliable when deployed as full mesh networks with ‘self-healing’ characteristics. Wireless tunnel sensors can take advantage of this as they can be configured to automatically connect to the nearest gateway and continue communication should there be an interruption. Sensor data is also buffered internally and uploaded automatically when wireless connectivity is restored.
• Security: Cybersecurity is a concern for both fixed-wire and wireless networks and especially with the growth in Internet connectivity through smart mobiles and tablets. Industrial Internet of Things (IIoT), 5G and Edge computing are also important applications that have driven developments in securing wireless connectivity. Wireless connectivity is now a common part of everyday life and can be accessed via password protected entry points in cyber-secure conscious industries including finance, healthcare, and local government. Within sever room and data centre environmental monitoring applications, products using Wireless Tunnel technologies tend to use the 128bit AES encryption algorithm and the only data transmitted is non-sensitive values collected via the environmental sensors.

Sever Room Temperature v Data Centre Environment Monitoring

Computer and server room monitoring applications are different in scale and the type of information required for environmental monitoring. Consider a small computer or server room with from 1-3 server rack cabinets. If each rack has about 5kW of IT load, at full utilisation there is around 15kW of cooling load in the room and a suitably sized air conditioner will have to be installed to maintain a comfortable ambient of around 18 to 25⁰C and humidity levels humidity of 40-60%.

Within this type of IT installation, temperature and humidity monitoring is typically achieved using a single environmental monitoring device at the server cabinet or room level. Data is reported to software hosted on the local computer network or remotely to a could based application. If there is a temperature or humidity reading outside a pre-set ‘safe’ range, an alert can be sent out to an email distribution list or as an SMS text message to set of mobile phone numbers and as SNMP traps. For larger server rooms it may be important to monitor door access and there may also be IP-based cameras in operation to provide visual records of events within the server room.

At the data centre level there could be 10-100 or more server cabinets to monitor and control. Over this larger type of application, it may be necessary to install multiple environmental monitoring sensors and to generate cabinet thermal maps showing temperature and humidity readings front and rear, top, middle, and bottom of the server cabinet as well as the front to rear differential temperature readings (ΔT) and within the hot and cold aisles where containment is installed. In such a more complex monitoring environment in a data centre, a wireless monitoring system can be easier and less costly to installed than a fixed wired installation. Cabinet level security could also be more important, especially in a colocation data centre and the environment monitoring software should include access control features where RFID door lock handles are installed to provide access to the server cabinets.

Summary

There’s a quiet revolution underway driven by developments in 5G, Edge computing and the Internet of Things (IoT). More and more devices are being connected using wireless technologies to generate data for analysis and automation. In server room and data centre environments, the most commonly installed environmental monitoring systems have been fixed wire systems, connected through RJ45 ports to the local IP network.

Several manufacturers of environmental monitoring systems for data centres now offer both fixed-cable and wireless communication features, either as part of an existing product or as a standalone product set. With wireless sensors offering lower cost per port monitoring and greater flexibility, it may only be a matter of time before wireless environmental monitoring systems become the dominate type within server room and data centre applications. Whilst there will always be concerns about cybersecurity within any critical environment including server rooms and data centres, the worldwide adoption rate of mobile phone banking apps shows just how quickly these fears can be allayed by speed, functionality and ease of use.