In its true form it allows the user or administrator to restore data to any point in time.
"[2] In an ideal case of continuous data protection, the recovery point objective—"the maximum targeted period in which data (transactions) might be lost from an IT service due to a major incident"—is zero, even though the recovery time objective—"the targeted duration of time and a service level within which a business process must be restored after a disaster (or disruption) in order to avoid unacceptable consequences associated with a break in business continuity"—is not zero.
[3] An example of a period in which data transactions might be lost is a major discount chain having card readers at its checkout counters shut down at multiple locations[broken anchor] for close to two hours in the month of June 2019.
CDP runs as a service that captures changes to data to a separate storage location.
True continuous data protection is different from traditional backup in that it is not necessary to specify the point in time to recover from until ready to restore.
"[1] Because "near-CDP does this [copying] at pre-set time intervals",[8] it is essentially incremental backup initiated—separately for each source machine—by timer instead of script.
When the interval is shorter than one hour,[11] "near-CDP" solutions—for example Arq Backup[12]—are typically based on periodic "snapshots"; "to avoid downtime, high-availability systems may instead perform the backup on ... a read-only copy of the data set frozen at a point in time—and allow applications to continue writing to their data".
There is debate in the industry as to whether the granularity of backup must be "every write" to be CDP, or whether a "near-CDP" solution that captures the data every few minutes is good enough.