Continuous Data Protection or CDP is a process for protecting data that provides more granularity than traditional backup.
CDP monitors primary data and tracks every change to that data in real time and making a copy of the data change as it happens.
The copy is usually stored in an indexed form. Specifically a base copy of the original data and then indexed increments of every time that data changed. This enables recovery to Any Point In Time (APIT) that the CDP process started.
CDP should track and copy changes at a block or byte level, if not it will make a copy of an entire file every time it changes – this is impractical for large files like databases or multi-media.
It is not a given that CDP can be a replacement for Replication as many CDP solutions do not work over distance.
Some CDP solutions do not maintain application consistency and as such are only suitable for file based data.
Robust CDP solutions provide APIT recovery which usually means Recovery Points split by seconds – essentially you can recover to any point in time with granularity of seconds. (Note: Traditional overnight backup only provides recovery points of every 24 hours)
Limitations of CDP will include just how much Any Point in Time Recovery they can store, typically this will be measure in days or weeks rather than months or years. This means CDP will cannot replace the functionality of long term archive.
