Definition - What does Cold Standby mean?
A cold standby is a redundancy method that involves having one system as a backup for another identical primary system. The cold standby system is called upon only on failure of the primary system.
Techopedia explains Cold Standby
Cold standby systems are turned on once to install and configure the system and data and then turned off until needed. Thereafter, it's employed only when updating noncritical data, which is done infrequently, or on failure of the primary system.
In contrast, a hot standby system is running simultaneously with another identical primary system. On failure of the primary system, the hot standby system immediately takes over to replace the primary. In such a setup, the data is mirrored in real time and both systems have identical data.
Also in contrast, a warm standby system runs in the background of the primary system and data is regularly mirrored to a secondary server. Therefore at times, the primary and secondary systems do contain different data or different data versions.