Continuous data protection

From ArticleWorld

Continuous data protection (continuous backup) is a special backup technique which progressively saves data on-the-fly, as it is written to the disk. Every change made to data recorded to disk is also recorded in a backup location, allowing data to be restored at any point in time. Essentially, we can say that it literally captures every piece of data that the user saves or modifies.

Continuous vs. traditional backup

Continuous protection is a special type of backup. Unlike traditional backup, which backups data at fixed time intervals, continuous data protection solutions backup data each time it is modified and saved. Therefore, if the necessary amount of backup storage space is provided, data can be restored from any point of time, while traditional backup solutions only allow data to be restored from a certain point of time (i.e. when the backup was made). While continuous data protection introduces a disk operation overhead (sometimes significant), it does eliminate the need of scheduled backups which slow down the system at a specified time. Some backup solutions are falsely marketed as continuous data protection, but they only allow data to be recovered from a certain moment, which is not real continuous data protection.

Continuous data backup may be less space-demanding than traditional backup solutions. This is because continuous data backup solutions save byte-level differences of the modified files rather than the files themselves. For example, changing 1 KB of a 20 MB file will only generate a 1 KB continuous backup file. However, this can prove risky if the original work is completely lost and no traditionally backed up data is available for restoration.

Continuous protection vs RAID

Although RAID also saves (mirrors/replicates) data on-the-fly, continuous backup solutions allow multiple copies of the data to be restored, not just the most recent one.