A rack-mount power distribution panel or rack power distribution unit (PDU) is a device with many outlets that distributes power to servers, storage devices, and network equipment located within a data center rack or cabinet. Analyst firm IHS divides them into two main categories:
1) Basic PDU provides reliable power distribution.
2) Intelligent PDUs offer features such as energy metering, environmental monitoring, and remote outlet control Intelligent PDUs can be divided into the following subcategories:
a) Metered Inlet PDU – Metered Inlet PDUs meter power at the PDU level and display the data locally and on the network. Metering helps users determine the power usage and available capacity of the circuits powering the racks, making it easier to configure equipment. By metering at the inlet level, users can avoid overloading circuits and easily calculate efficiency metrics such as power usage effectiveness (PUE).
b) Metered Outlet PDUs – Like metered inlet PDUs, metered outlet PDUs help users determine rack power usage and available capacity and facilitate configuration. The main point is to enable users to understand the actual power consumption at the device or server level, so that efficiency can be compared and costs can be allocated to specific business units or customers.
c) Switched PDUs – Switched PDUs have the functionality of a metered inlet PDU and also provide controlled on/off switching of individual outlets or groups of outlets. They enable authorized users to remotely reboot devices in a specific order, provide power sequencing delays to reduce inrush current, and prevent unauthorized device configuration. They are critical in remote and colocation facility deployments because they allow you to quickly restore service by rebooting servers. Unused equipment can be remotely shut down to save energy.
d) Switched PDU with Outlet Metering – A Switched PDU with Outlet Metering combines all the features of a Switched PDU with the features of an Outlet Metered PDU. Each subcategory of Intelligent PDUs has features that can help data centers reduce operating costs, increase uptime/availability, improve mean time to repair (MTTR), increase energy efficiency, and manage existing capacity.
Why is it important to choose the right PDU?
Finding better long-term value
As IT buyers struggle with smaller budgets, lower price is often a deciding factor. Since basic PDUs retail for a lower price, it may seem like a better deal to buy them. Others may not be convinced that the features of intelligent rack PDUs provide additional value, or their organizations don’t have the time or resources to benefit from them. As a result, many buyers choose basic PDUs, even though intelligent PDUs can provide greater value and cost savings in the long run.
To understand why intelligent PDUs are a better choice, we must first examine the common problems they can solve. Major challenges that almost all data centers face today
One of the most important goals of a data center is to ensure business continuity. Rack PDUs help achieve this by providing stable, reliable, and sufficient power to all the equipment plugged into them (servers, storage, and networking equipment). However, there are some other major challenges facing data centers to consider as well.
• Power capacity management and configuration
• Energy management
• Environmental management
• Physical and cyber security
• Computing power requirements
• Asset and change management
Power Capacity Management and Provisioning – Many data centers grow in a chaotic and unplanned manner. Technicians often plug new equipment into the first available outlet with little knowledge of the available power capacity. This can cause fuses to blow and lead to downtime. In 2013, the average cost of downtime was a staggering $7,908 per minute.
Energy Management – Many data centers support more infrastructure than necessary. One research report found that the average server runs at only 12-18% of capacity. Therefore, adopting several practices can reduce power consumption by up to 40%.
Environmental Management – While IT equipment accounts for 50% of energy costs, another 37% is spent on cooling and circulating air. Data centers are often overcooled to prevent equipment failure, but raising the thermostat temperature by one degree Fahrenheit can save up to 3% of current energy costs.
Physical and network security – The need for secure access control to cabinets and aisles is rising. In 2011, Health Net, Inc., a publicly traded U.S. healthcare company, reported that the personal health records of up to 1.9 million people nationwide were compromised due to the loss of multiple server drives in a data center it managed.
Demand for computing power – While data centers continue to shrink and expand, one constant for the foreseeable future is the need for more computing power, and this rapid expansion will require far more power than data centers have experienced in the past.
Asset and Change Management – Manually tracking assets can be cumbersome and costly for a growing data center. One study found that the process of inventory collection, inventory reconciliation, finding misplaced assets, manual repository updates, and replacing misplaced assets cost $714,000 and approximately 706 work days per year .