Hotswapping

Hotswapping refers to the ability to add, remove, or replace components of a system while it is powered on and operating. The term encompasses hardware changes, such as swapping drives or modules, as well as software techniques that replace parts of a running program without a restart. Versions of the term are also written hot-swapping or hot swapping in different contexts.

In hardware contexts, hot-swapping relies on compatible backplanes, hot-swappable drive bays, and controllers that can handle live changes. It is common in enterprise storage arrays, servers, and telecommunications equipment. External devices such as USB flash drives, USB hard disks, and SD cards are widely considered hot-swappable on many consumer and business systems. Safe hot-swapping typically requires the operating system and firmware to quiesce the device, followed by a proper logical detachment or unmount, before physical removal. Proper procedures help prevent data loss and hardware damage. Not all components are hot-swappable; some devices require powering down, and attempting removal without support can risk data corruption or equipment failure.

In software contexts, hot-swapping describes replacing or updating parts of a running program or environment without stopping service. Examples include dynamic code reloading, plugin replacement, and zero-downtime deployments in certain frameworks and platforms. This approach can reduce maintenance windows but introduces complexity around state, resource cleanup, and compatibility. Languages and systems vary in their support: some offer built-in hot-swap capabilities, while others require external tooling or architectural patterns such as service orchestration and rolling updates.

Overall, hot-swapping aims to minimize downtime, but it demands appropriate hardware, software support, and careful procedures to maintain reliability and data integrity.