Warm Standby
A disaster recovery strategy that keeps a scaled-down but fully functional version of the production environment running at all times, ready to scale up on failover.
Definition
Warm Standby keeps a minimal but functioning copy of the production environment running continuously in a secondary region: not the full-scale production capacity, but enough that it can be scaled up quickly during a failover, rather than built from scratch. It sits between Pilot Light (infrastructure defined but not running) and full Multi-Site (both environments running at full capacity), trading a moderate ongoing cost for a meaningfully faster recovery time than colder strategies allow.
In Practice
An e-commerce platform might run a warm standby at 10% of production capacity, sufficient to serve traffic immediately after failover while additional capacity scales in behind it.