Definition

hot swap

What is a hot swap?

A hot swap describes the act of removing components from or plugging them into a computer system while the power remains switched on. This means that parts can be changed without shutting down or rebooting a computer or server

Hot swap is sometimes called "hot plug" and "hot insertion." However, hot plugging describes the addition of components only.

What is hot swappable?

Hot swappable components include network adapters, Universal Serial Bus (USB) devices (like a  keyboard) and external hard drives, among others. Hot swap is a required feature in fault-tolerant systems with redundant components such as circuit boards, hard drives, etc. This is also true for servers that are powered 24/7/365, or all day, all year long. 

How does hot swapping work?

Hot swap is a key feature of USB devices that allows the addition of peripheral hardware without having to shut down the system. So, when a component in a server fails, the redundant unit automatically takes over. Flawed or failed hardware can be replaced without disruption.

Hot swapping works by providing a rack or enclosure for the device that gives the appearance of an uninterrupted connection to the computer's bus or controller. The system thinks that the device is intact while it's being removed or replaced. 

Even shared devices on a local area network (LAN) can be hot swappable. Hot swap arrangements are sold for both Small Computer System Interface (SCSI) and Integrated Drive Electronics (IDE) hard drives. Hot swap versions of redundant arrays of independent devices (RAIDs) are also available.

An image of a hard drive in a RAID array.
Hot swappable RAIDS allow users to swap out drives without turning off power.

Examples of hot swappable devices

The are many kinds of hot swappable devices, including hard drives, keyboards, printed circuit boards and more.

What is a hot swappable hard drive?

Hot swap hard drives allow users to remove or replace a hard drive without disruption or powering off the device. If a drive in a storage array fails, the system uses a redundant drive. Hot swappable drives are identified with a purple tab.

What is a hot swappable keyboard?

Hot swappable keyboard switches allow users to personalize their keyboards. These mechanical keyboards allow users to switch hot swappable keys by using a switch puller. Switches and plugs can be removed and replaced with new ones without having to disconnect the keyboard from a desktop. 

What is a hot swap printed circuit board?

A printed circuit board (PCB) makes hot swappable keyboards possible. At its most basic, hot swap PCB means that there are special sockets that allow a user to pull out the switch or click into place without soldering it onto the circuit board inside. This means that you can quickly change switches on demand without much effort. 

What is a hot swap controller?

Hot swap controllers protect circuits from the dangers of sudden changes in power supply. This type of integrated circuit (IC) monitors over or under voltage conditions. It also rapidly opens and closes switches when it is considered unsafe.

What is a hot swap SSD?

A hot swappable solid-state drive (SSD) is a solid-state storage device that leverages IC assemblies to ensure persistent data storage. The flexible nature of Serial Advanced Technology Attachment (SATA) drives make hot swappable Hard Disk Drives (HDDs) or SSDs a viable option for an extensive range of applications.

integrated circuits by generations
Integrated circuits within hot swap controllers make hot swapping possible by monitoring the voltage conditions to ensure protection from sudden changes in power supply.

Can a SATA drive be hot swappable?

Not all SATA drives are hot swappable, but most are hot pluggable. Hot swappable SATA drives require a controller and a compliant power source. What makes a SATA drive hot swappable is its ability to sense the device's presence in a port without turning the SATA hard drive’s power on.

What is a hot swap drive bay?

A hot swappable drive bay is a standard-sized case that allows users to add or replace computer hardware.

This was last updated in November 2021

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