Continuous Data Protection
How Continuous Data Protection Records Each Change
Continuous data protection (CDP) is a backup approach that captures each change to a set of data as it happens, instead of copying the data at fixed intervals. Each write is recorded, so the system can roll back to almost any point in the recent past, not only to the last scheduled copy.
Traditional backups copy the data every few hours or once a day. Anything written between two copies can be lost if a failure happens in that gap. CDP narrows the gap, often to seconds, by recording changes continuously and storing that record separately from the live data.
CDP Compared with Near-Continuous Snapshots
Many systems offer something that looks similar: snapshots taken every few minutes. These are sometimes described as near-continuous protection. The differences are in how they work.
- Frequency. True CDP records changes as they occur. Snapshots are taken at set intervals, so the recovery point is the most recent snapshot.
- Granularity. CDP can usually restore to a specific moment between events. A snapshot restores to the moment it was taken.
- Overhead. Continuous logging adds work and storage for every write. Frequent snapshots add load too, especially on busy disks.
Both reduce how much data can be lost. Which one suits a system depends on how often its data changes and how precisely it must be restored. Snapshots themselves are explained in snapshot vs backup.
Where CDP Fits in a Backup Plan
CDP is most useful for data that changes often and is costly to lose, such as transaction records or active user content. It is not a complete answer on its own. A continuous record is only as useful as its history: if the change log is short, or can be edited by the same attacker who altered the data, it may not help against deletion or ransomware.
For that reason CDP is usually combined with periodic full copies stored offsite. The 3-2-1 backup rule still applies to continuous systems, and recovery targets are described in RPO vs RTO.
Frequently asked questions
Is continuous data protection the same as continuous backup?
The terms are often used loosely. CDP generally refers to systems that record every change so you can restore to any point in a recent window. A continuous backup may simply mean frequent scheduled copies. Check exactly what a product records and how far back it can restore.
Does CDP replace regular backups?
No. CDP narrows the gap between backups and makes recovery more precise, but it usually keeps a limited history and depends on the system it runs on. Regular, independent full copies stored offsite are still needed for long-term recovery and for disasters that affect the whole environment.