Continuous data protection (CDP) is a backup and recovery technique that automatically replicates and timestamps every change on critical datasets. Also known as continuous backup or real-time backup, this technique allows organizations to roll back to a specific time for their dataset before undesirable incidences, such as data corruption, user mistakes, or malware, have occurred. CDP’s goal is to capture every version of the data corporate users save to create recovery points that will be available in case of disasters and unwelcome surprises.

What is continuous data protection?

Continuous data protection is a backup and recovery storage method that regularly saves all data in an organization. CDP creates an electronic journal of complete storage snapshots or one storage snapshot for each moment in time that data change occurs. The CDP was patented by British entrepreneur Pete Malcolm in 1989 as “a backup system in which a copy of every change made to a storage medium is recorded as the change occurs.”

CDP services operate as a one-stop shop for preserving changes to data in a separate storage location. Different technologies capture continuous live data changes in various ways, catering to distinct needs. CDP-based solutions can restore objects of various granularities, from crash-consistent images to logical items such as files, mailboxes, messages, and database files and logs.

How does continuous data protection work?

When you make a first comprehensive backup of your data, continuous data protection runs in the background, taking note of every change made within a specific time frame and writing it down to a journal file. You may conveniently roll back your system to the desired point by recording all changes until a failure. The automated, continuous recording of changes provides the ability to recover data to a much more intricate level than other backup methods that restore to a previous checkpoint.

Companies must be able to create off-site backups to preserve business continuity. Although most CDP servers are located in an organization’s own data center, many can produce secondary tape backups or replicate backups to the cloud or a backup data center. Backup redundancy is critical to disaster recovery and allows you to continue operating should something happen to the organization’s primary backup and recovery server.

Advantages and challenges of continuous data protection

There are advantages and drawbacks to utilizing continuous data protection like any other technology. However, in most cases, the benefits greatly outweigh the challenges.

Whether you need to go back in time and retrieve data from before the damage or need to recover the last clean version before a ransomware attack, continuous data protection has advantages over other backup techniques. The main advantage of CDP is a near-zero recovery point objective (RPO). Because continuous data protection is always on, your backup copy is kept up to date, allowing CDP to recover data in real-time if you suffer a loss.

Another advantage of CDP is that it removes the difficulties associated with backup windows, the periods set aside to back up data (such as overnight). New data may be lost or damaged during these scheduled backup windows if no continuous data protection is used. CDP protects against malware and ransomware, as well as accidental data deletion.

Continuous data protection, on the other hand, isn’t the end-all of backup. It does have certain drawbacks, however. First and foremost, it necessitates physical disk storage with fast performance that may increase costs. Because the data is kept on a server, that server might be a single point of failure. It’s critical to ensure that your data is constantly accessible to avoid taking a risk. CDP also places more strain on your data resources. Because every change or a fresh piece of data is recorded and backed up in real-time, your data transfer rates are effectively doubled—which might impact system stability or performance.

Advantages of CDP

• Ransomware, malware, and other data corruption causes can be avoided.
• Eliminates the need for a backup window of traditional backup approaches.
• Easy to roll back and restore.
• Generates healthy restore points.
• All inputs and outputs to the selected virtual disks are recorded and timestamped.
• It’s not dependent on the operating system or applications to work.
• There’s no need to stop or interrupt programs.
• There is no need for any hosting agents.

Challenges of CDP

• Smaller organizations may have a hard time accessing CDP solutions.
• A CDP backup server may become a single point of failure if not properly designed.
• It might impact the systems’ stability or performance.

Differences between continuous data protection and traditional backup

Continuous data protection differs from traditional backup in that you don’t have to select a time to restore until you’re ready to restore. Traditional backups only recover data from the moment the backup is made. In contrast to the traditional backup, which takes snapshots of a dataset or system as restore points, continuous data protection does not have backup schedules. Data is simultaneously written to another location over the network or an appliance. This adds a little overhead to disk write operations but eliminates the need for scheduled backups.

CDP is the gold standard for backup and restoration. However, nearly CDP technologies can provide enough security for many businesses with less complexity and cost. Snapshots may, for example, provide reasonable CDP-level protection for file shares, allowing users to access data on the file share at regular intervals—for example, every half hour or 15 minutes. That’s an excellent protection level, exceeding tape- or disk-based nightly backups. It might be all you require. Because near-CDP performs this at pre-set time intervals, it is essentially an incremental backup that is started by a timer rather than a script.

Continuous vs. near-continuous data protection

Backup write operations at the level of the basic input/output system (BIOS) of the microcomputer are carried out in such a manner that normal computer use is not affected; thus, true CDP backup must be run in collaboration with a virtual machine or equivalent— ruling it out for typical personal backup software.

Because they automatically take incremental backups at pre-determined intervals, some solutions marketed as continuous data protection only allow restorations after a set period, such as 15 minutes, one hour, or 24 hours. Because they don’t give the capacity to recover to any point in time, “near-CDP” techniques that provide only a short duration of protection aren’t recognized as genuine continuous data protection. When the time between snapshots is less than one hour, “near-CDP” methods are typically based on periodic “snapshots,” during which data is copied to a read-only copy of the data set frozen at a specific point in time—and applications may continue to write to their data.

There is uncertainty in the business as to whether an “every write” granularity is required for CDP or whether a “near-CDP” solution that captures data every few minutes is sufficient. The latter is known as near-continuous data protection. The ambiguity in the definition of continuous is whether only the backup process must be continuously automated, which is usually sufficient to provide the benefits mentioned above, or whether the ability to restore from a backup also has to be continuous. The Storage Networking Industry Association (SNIA) uses the term “every write.”

CDP vs. modern backup technologies

Continuous data protection differs from RAID, replication, and mirroring in that these methods only protect one copy of the data (the most recent). If data becomes damaged in a way that is not immediately recognized, these technologies merely safeguard the inaccurate information with no technique to recover an unaltered version.

Continuous data protection addresses some of the negative consequences of data corruption by allowing for the recovery of a previous, uncorrupted data version. Transactions that occurred between the corrupting event and the restoration are lost. They might be recovered with other methods, such as journaling.