Also known as an offline backup, a cold backup is a method of creating a secondary copy of data contained within a given database or computer system. This strategy is different from some other backup processes, in that the system and the data is not accessible while the backup is in progress. Once the cold backup is complete, end users can log back into the system and access the data at will.
The cold backup is the opposite of what is known as a hot backup. With a backup that is hot, the system is continuing to operate and users can freely access data during the backup process. With many systems, users are likely to experience at least some additional time lag in retrieving information, since a portion of the system resources are in use with the backup process. With a hot backup, additional care must be taken to capture any changes or additions that users enter during the backup process. Businesses that are open around the clock often prefer to go with the hot backup strategy.
For businesses that prefer to use a cold backup process, the activity typically takes place once the business day is complete. Companies that operate around the clock may choose to schedule the backup for early morning hours, when users are the least likely to require access to the system. This approach helps to minimize the potential for the backup to prevent employees from assisting customers as the copying is taking place.
A cold backup may be conducted using a preset schedule that identifies the specific time for the backup to automatically initiate. For example, the backup may be configured to begin each morning at 2:00 a.m., providing time for the action to complete before employees begin to arrive for the beginning of the business day. It is also possible to conduct a cold backup on a demand basis. This approach is often helpful when there is a need to refrain from initiating the backup until specific tasks, such as updating data in a billing system, is completed for the business day.
Attempting to access a computer system while a cold backup is in progress can produce several different results, depending on how the system is configured. In some cases, the system will simply not allow the login attempt to complete. Other systems may allow the login to override the backup process, effectively bringing the backup to a halt. Typically, it is not recommended to interrupt a cold backup in progress, since this could result in losing data, of even causing the system to lock or freeze for a short period of time.