What Is a redundant power supply?
Redundant power supply means that equipment such as servers and network switches on a network, which have a large impact on others even in the event of a momentary power failure, have two or more power supply units to provide a safer measure against power supply problems.
It may also refer to a system in which, in the event of a power failure in a hospital or factory where the electricity supply from the power company has been cut off, a private power generator is activated to secure the minimum necessary power and wait for the electricity supply to be restored.
In the IT field, “redundancy” refers to the provision of backups in advance to minimize the impact of a single system or device that fails or otherwise becomes inoperable, thereby enhancing safety.
In this section, the term “equipped with a redundant power supply” refers to the power supply for individual devices such as servers and network switches that have multiple power supply units built into the device and can respond to power supply problems, and the technologies and products related to this are described.
Uses of Redundant Power Supplies
When an unexpected power failure occurs in a computer, data that was being processed in memory is lost. For computers like servers that send and receive data to and from many computers and IT devices, a loss of data integrity requires a great deal of effort to recover.
When a hard disk is reading or writing data, if the power is turned off, the data in that sector will be lost, and headers can fall onto the disk surface, causing the entire disk drive to fail. Similarly, if a network switch that relays data over the network loses power, the network will be severely affected.
To prevent the impact on networks and data processing caused by power supply-related problems, redundant power supplies are provided for servers, network switches, and other equipment that would suffer more damage in the event of a failure.
Principle of Redundant Power Supplies
Redundant power supplies built into servers and network switches incorporate two power supply units of the same standard. Each power supply unit is connected to the power supply at all times and supplies electricity to the baseboard and other devices built into the device. If one of the power supply units should fail, the non-failed power supply unit will supply power to the equipment that was served by the failed power supply unit.
Therefore, a single power supply unit must be capable of providing the power needed by the entire equipment by itself. However, in the case of rack-mounted servers, where many units are built into a single rack, each individual unit is described as a device.
Most units that support redundant power supplies also support hot-swapping of power supplies. In equipment that supports hot-swapping, a failed power supply unit can be replaced without powering down the equipment, so there is no equipment downtime associated with replacing the power supply unit.
Even if you have equipment with redundant power supply units built in this way, it will not be able to respond in the event of a power failure. In large data centers and factories, electricity sent from the power company is separated into two systems when it is drawn into the premises, so that electricity supplied to the equipment will not be interrupted in the event of a failure in either system. An uninterruptible power system (UPS) is installed between one of the redundant power supply units and the power outlet to allow for power outages for a certain length of time.
How to Select a Redundant Power Supply
Even if a redundant power supply is built into the equipment, it is not enough to completely prevent power supply-related problems. In order to prepare for power supply-related problems that may occur within the premises, the power supply system must be separated from the original. In addition, a UPS is necessary to prepare for power outages from the power company.
Thus, when selecting a redundant power supply, it is important to assume various risks, consider the necessary preparations for the entire power supply system, and select a redundant power supply based on its position in the system and expected effects. On the other hand, power supply units also have the role of stably supplying electricity to devices even when power supply fluctuates slightly. It is also important to examine the performance and specifications of the power supply unit as a standalone unit.