Packet Power Blog


Say what? Data center acronyms clarified

Posted on Thursday, April 20, 2017 by Alan Katz

When using industry jargon, it can be laborious to verbalize each individual word. This is why every industry has a unique set of acronyms and expressions. But even the most experienced professional can get caught off guard by a new term or an old abbreviation. Whether you're new to the data center industry or feeling out of the loop in jargon-heavy discussions, read on for clarity.

A - Amps
The flow rate of electricity.

AC/DC - Alternating Current/Direct Current
Current flow
is either alternating or direct. AC/DC is also a great rock band.

ASHRAE - American Society of Heating, Refrigerating & Air-conditioning Engineers
An institution that develops guidelines and standards for data center environments.

ATS - Automatic Transfer Switch
An automatic electrical switch positioned near a back-up generator that switches a load to the back-up generator from the utility source if the utility source fails to provide temporary power.

BMS - Building Management System
Computer-based control system that monitors a building's electrical and mechanical equipment.

BTU - British Thermal Unit
A unit of energy (1 kWh = 3,412 btu). See "kWh"

Cabinet - also referred to as a Rack
The most common means of housing servers and many other types of IT (Information Technology) devices within a data center. See "U - Rack Units"

CFD - Computational Fluid Dynamics
A technique used to model, usually as a simulation, the way in which air will move heat through a data center. The output is often expressed as a colorful heat map.

Containment system
A means of separating cooler air from warmer air with an aim to improving overall cooling system performance. There are many types of containment systems including aisle-based, chimney, in-rack and liquid cooled.

CRAH/CRAC - Computer Room Air Handler/Computer Room Air Conditioner
Equipment used to manage temperature, humidity and air pressure in facilities.

CT - Current Transducer or Current Transformer
Current transducers measure current on AC circuits.

DCiE - Data Center infrastructure Efficiency
The inverse of PUE (Power Usage Effectiveness). It is calculated by dividing Information Technology Equipment Power by Total Facility Power. See "PUE"

DCIM - Data Center Infrastructure Management
The name of the game. Also a term used to describe ERP (Enterprise Resource Planning) systems for data centers.

Hot spot
A club or restaurant that is difficult to get into. More often for folks working in data centers, hot spot refers to an area in the data center where the temperature exceeds desired levels.

HVAC - Heating, Ventilation & Air Cooling
Technology and infrastructure that attempts to provide the optimal indoor environment.

IEC - International Electrotechnical Commission
An international non-profit, non-government organization that prepares and publishes standards for all electrical, electronic and related technologies.

IECC - International Energy Conservation Code
Highly recognized model code for energy efficiency design, construction, maintenance and operation.

IoT - Internet of Things
Interconnection via the Internet of many types of wireless devices.

IP - International Protection rating
An IEC classification used to express how well an item resists water and dust. It is used for many things including the "pin and sleeve" connectors that are common in data centers. IP can also stand for "Internet Protocol" and "Intellectual Property".

A standard communications protocol used for transmitting information between electronic devices and is manufacturer agnostic. See "SNMP"

PDU - Power Distribution Unit
A source of confusion as it can mean a large floor-standing device that may incorporate a transformer and manage distribution of power to over 100 racks. Or, PDU can refer to a single rack-mounted device with multiple outputs designed to distribute electrical power to the devices in a cabinet.

PUE - Power Usage Effectiveness
Calculated by dividing Total Facility Energy Usage by IT Equipment Energy Usage. There's a good deal of controversy on this metric, but it remains the most common means of rating a data center's energy efficiency.

RCI - Rack Cooling Index
Measures the degree to which equipment racks are cooled and maintained compared to industry benchmarks.

Rh - Relative humidity
Water content of the air relative to what it could be before it condenses at a given temperature. The temperature at which water in that same air mass would condense (form a fog) is called the dew point.

RPP - Remote Power Panel
Same concept as a floor-standing PDU but without a transformer. See "PDU"

SAN - Storage Area Network
A dedicated high-speed network that interconnects and presents shared pools of storage devices to multiple servers.

SLA - Service Level Agreement
A contract between an end user and service provider that specifies the level of service expected from the service provider.

SNMP - Simple Network Management Protocol
A standard developed in part to provide a common means for gathering data from equipment made by different manufacturers. SNMP is currently on its third major version. See "Modbus"

ΔT - Delta T
The difference or change in temperature across a device.

THD - Total Harmonic Distortion
A measure of how much your load is distorting the perfect waveform of the power provided by your utility. Typically measured for both current (THDi) and voltage (THDv).

U - Rack Unit
The measuring mechanism for vertical rack space. 1U is equal to 1.75 inches (44.45 mm) of vertical rack space. Fun fact, 1U is exactly equal to 1 vershok. Packet Power will present a free gift to the first person who emails us with the correct explanation of a vershok.

V - Volts
The pressure of electricity. Named after Alessandro Volta, the voltage of household power ranges from 100 to 240V around the world. It can vary even more within data centers.

Watts / Kilowatts
The measuring mechanism for power and named after James Watt. A kilowatt (kW) is 1,000 Watts. The average United States household uses 1kW of power every hour, which is also the amount of power received from the sun on one square meter of earth near the equator on a clear day.

kWh - kilowatt hours
The measuring mechanism for energy, equivalent to one Watt being used for one hour multiplied by 1,000. Electrical energy is usually sold in kWh. See "BTU"

We hope this list is helpful to you and your team. Did we miss your favorite (or least favorite) acronym? Let us know, and we'll add it to the list.

Contact if you'd like clarity on how Packet Power can help you monitor what matters most to you.

Topics: data center operations, Data center power, DCIM