Hotaddable

Hotaddable describes hardware or software resources that can be added to a running system without powering down. It encompasses the ability to increase capacity or add functionality while the system remains online, including memory, CPUs, storage, and peripheral devices in various computing environments. In virtualization, hot-add commonly refers to extending resources allocated to a running virtual machine, such as adding virtual CPUs or increasing memory, and may also cover adding virtual devices like network interfaces or storage.

The availability of hot-add depends on multiple factors. Both the host infrastructure and the guest operating system must support live reconfiguration, and the virtualization platform must expose and manage the feature. Some hot-add operations can be performed with minimal interruption, while others may incur brief pauses or require reallocation activities. Limits may apply, including maximum resource sizes, compatibility with the guest OS, and hardware or firmware constraints.

Hot-add is related but distinct from hot-plug. Hot-plug usually describes the addition or removal of devices, often through physical connections, while hot-add focuses on increasing the capacity of an existing resource. In practice, many data center and cloud platforms combine hot-add with other dynamic scaling features to reduce downtime and improve scalability, provided that the underlying hardware, firmware, hypervisor, and operating system all support live reconfiguration.