Definition
A warm standby is a disaster recovery strategy where a secondary system is kept running and updated with data but is not actively processing live traffic. This setup involves having hardware and software ready to take over, with data replication ensuring minimal data loss. In practice, the standby system is activated and scaled up to handle user requests when the primary system fails. This approach is crucial for maintaining business continuity and minimizing downtime without the full cost of a fully active redundant system. For example, a warm standby database might receive regular backups and transaction logs from the primary, ready to be promoted if the main database becomes unavailable. It differs from a cold standby, which requires significant setup time, and a hot standby, which is fully active and mirrors the primary in real time. Understanding warm standby is essential for cloud architecture and disaster recovery planning, appearing on exams like the AWS Certified Solutions Architect Associate and CompTIA Cloud+.