Continuous data protection (CDP), also called continuous backup, is a storage system in which all the data in an enterprise is backed up whenever any change is made. In effect it creates an electronic journal of complete storage snapshots, one storage snapshot for every instant in time that data modification occurs. A major advantage of CDP is the fact that it preserves a record of every transaction that takes place in the enterprise. In addition, if the system becomes infected with a virus or trojan, or if a file becomes mutilated or corrupted and the problem is not discovered until sometime later, it is always possible to recover the most recent clean copy of the affected file. Installation of CDP hardware and programming is straightforward and simple and does not put existing data at risk.

Continuous data protection minimizes the amount of data that must be backed up within each cycle and effectively eliminates the backup window. As such, backups occur every few minutes, as opposed to once per night.

CDP works by incrementally backing up the changes in the state of the data over some period of time or when a record, file or block of information is created or updated. In some cases, there is only one initial full backup and all subsequent backups are incremental to the original backup. This approach is in contrast to the standard techniques for data backup, but has been gaining greater adoption. Continuous data protection systems can be block, file or application based.