Rack/cabinet monitoring over LAN and LTE

With any electrical equipment and devices packed into confined space, there are several things to monitor. But the most important parameters would always be:

• Temperature

At several spots (sensors) if possible. It can vary by 10 degrees Celsius if you place a sensor probe next to air input, air output or hotspot. 

• Relative Humidity

Again sensor location is important (air input or output).

• Water Detection
• Power (presence)
• Physical Security
   
• Optical smoke detector (optional)

And, of course, there should always be a convenient way to alert the responsible person in case anything goes wrong with a single monitored parameter, or all of them. The best way to remotely analyze different parameters is a graph (chart) with all sensor values, we call it multigraph.

Based on HW group’s customers experience, we propose a recommended rack monitoring solution for small and large racks.

Let’s go through individual solutions and their components.

Small 10"/19" Rack

In a small rack monitoring solution we are interested in monitoring few critical parameters: power, temperature, relative humidity and physical security, with the option of sending alerts via SMS and calls.

For detailed power consumption monitoring and control, we recommend using NETIO PDUs. If a remote PDU is not required in the rack, you can use the PowerEgg2 sensor to detect power presence or whole power monitoring can be excluded.

For environmental monitoring in a small 10"/19" rack, we recommend using the Perseus Monitoring 140.

It is a powerful LAN monitoring device with all the features needed in an IT environment.

In a small rack only two sensors and one detector are needed:

1. Combined Temperature and RH (Relative Humidity) sensor, either in rack version or installed on a cable. We recommend installing such a sensor in the lower part of the rack (air input), where higher humidity levels, at the brake of the dew point, could be expected.
2. Second Temperature sensor placed at the hottest air spot in the rack - usually at the top of the rack next to air output or next to most heating device (hot spot).
3. Door contact detector unit for controlling door state. It’s useful to have a log of every single issue when a door on your server was opened. 

 SMS and Call alerts are available by adding the SMS gateway in GSM or LTE version. The second option is to replace Perseus 140 by 145 with the included LTE modem. Several other HWg products in one network (LAN) can use a single SMS gateway to send SMS alerts or call alerts to a phone number.

E-mail alerts from the Perseus Monitoring 140 can be sent via the external SMTP server (public or private). However, instead of sending email alerts from smtp.gmail.com (or any other public SMTP server), use the free portal service (HWg-cloud.com) for more long-term reliable email alerting. The Portal additionally supports device invalid alerts (the Portal will email you if the device is unreachable for 1 hour). If there is a connection or power outage on the remote monitoring site, the Portal will send an email to the person responsible for maintenance.

Large 19" Rack

Same as in the small rack, in the large rack we are interested in monitoring the same parameters, alas at a larger scale. As a valuable addition, there is also a WLD zone input, which alerts the responsible person if water is detected (even a small volume of conductive liquid along the entire length of the WLD sensing cable).

For detailed power consumption monitoring and control, we recommend using NETIO PDUs. If a remote PDU is not required in the rack, you can use PowerEgg2 sensor to detect Power presence or whole power monitoring can be excluded.

For environmental monitoring in a large 19" rack we recommend the Perseus Monitoring 155.

It is a top-of-the-line monitoring device with all the features needed in an IT environment. And it supports LTE communication with Ethernet in one device, which means that backup cellular communication is available right out of the box, as well as SMS and call alerts.

In a large rack 4 sensors and one detector are needed:

1. Combined Temperature and RH (Relative Humidity) sensor, either in rack version or installed on a cable. We recommend installing such a sensor in the front/lower part of the rack (air input), where higher humidity levels, at the brake of the dew point, could be expected.
2. Second Temperature sensor placed at the hottest air spot in the rack - usually at the top of the rack next to air output or next to most heating device (hot-spot).
3. Door contact detector unit to control door state (multiple door contacts can be connected to a single DI).
4. Two WLD sensing cables are also installed, one directly connected to Perseus unit monitors the floor under the rack, and the other one, connected via a WLD Relay, is placed in a dripper under the air conditioning unit, especially if it is located above the rack, to monitor condensation and possible coolant leakage.

On top of that, in larger racks, everything is usually powered by a 1-phase electricity meter. With the Perseus Monitoring 155 unit, there is an opportunity to use a rather cheap but reliable electricity meter with RS-485 (Modbus/RTU) interface to send the data to Perseus for further analysis and alerting.

Summary

Any system you install will not help if it is not installed properly. We understand that our customers who are responsible for IT infrastructure in small / medium size companies do not install remote monitoring system every week. 
However, you invest your time and money in this system just to be sure that the alert message will be delivered even 7 years after the installation. What you need is an easy to install, robust and long term reliable monitoring system. 

As HW group CEO Jan Rehak says: “It's simple physics, all you have to do is follow 4 simple rules”:

1. Place at least 2 temperature sensors and name them.
2. Use graphs (Portal) to analyze remote locations (you will not remember it a month later).
3. Test the system once per year (just with the cup of hot water). 
4. Email alerting is fine, but please avoid emailing via free public SMTP servers (smtp.gmail.com and similar) for anything professional.

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