Setting up a small server room: power, UPS, earthing and cooling

Many network outages and equipment failures in small and medium organizations start not with the servers themselves but with unstable power, excessive heat or poor earthing. Check these four areas before buying expensive equipment.

Temperature and airflow

Common industry guidance (ASHRAE) recommends an equipment inlet air temperature between 18 and 27 °C. Cooling more than necessary only raises the electricity bill.

• The front of the racks should face the cold air intake and the back should exhaust hot air, without hot air circulating back to the front.
• Close empty rack spaces with blanking panels so hot air does not recirculate inside the rack.
• Do not rely on a household split air conditioner as the only cooling for a server room, or at least have a backup unit and a temperature alarm.

Sizing a UPS

Add up the power consumption of all equipment in watts and add about 20 to 30 percent for growth and safety margin. Note the difference between volt-amperes (VA) and watts (W): a UPS's watt rating is usually lower than its VA figure. Set the backup time (runtime on battery) based on the time needed to shut servers down safely or for a generator to start.

For sensitive equipment, an online (double-conversion) UPS provides more stable output power. Batteries have a limited life and must be tested and replaced on schedule.

Earthing

A proper earthing system protects equipment and people from electric shock, noise and surges. The permitted earth resistance is set by the project's technical specifications and national building regulations; telecom installations and data centers usually target very low values. Measure and document the earth resistance after installation and re-measure it periodically.

Monitoring and maintenance

• Install a temperature and humidity sensor with SMS or email alerts.
• Feed the racks from dedicated, labeled circuits.
• Keep cables tidy and documented so troubleshooting is fast.

A small but well-designed server room is more reliable than a large, disorganized one.