What Is Continuous Data Protection (CDP)?
Data backup has evolved from punch cards and magnetic tape to floppy disks and hard drives, and now to cloud-based solutions that eliminate the need to keep large machines humming in an on-premises data center. Traditional backups were usually done at night to minimize impact on the production IT system, creating a lag of up to 24 hours.
Continuous data protection is a system that backs up data every time a change is made. CDP keeps an ongoing record of data alterations and makes it possible to restore a system to any previous point in time. It effectively removes the traditional interval between two scheduled backups.
“Continuous data protection copies … any changes to your data, from source to target,” notes Cloudian, a hybrid storage provider. “True continuous data protection systems record every write and store it in a changelog on the CDP system. CDP keeps all changes until the last write before failure, allowing you to restore to that point or any previous point before the data was corrupted or lost.”
Here, an IT manager must make a decision about the hierarchy of storage needs, say experts.
“Not every kind of data needs a two-second recovery point objective,” says Rick Vanover, senior director of product strategy for Veeam. “CDP is not a solution for all potential incidents. If you lose a file, standard backup is best. That’s the daily disaster.”
The primary downside of CDP is that it offers a single point of failure. If the CDP software gets corrupted, your data can become toast. It’s generally recommended to use data backups for storage even when using CDP, Vanover says.
Keeping an extensive record of CDP changes is also expensive, says Mark Chuang, VMware’s head of product marketing for cloud storage and data. And it can be dicey to find a safe backup point in the most common form of attack. “Ransomware can have very long dwell times. Some bits already may have been infected or encrypted.”
For this reason, Gartner recommends the use of isolated recovery environments on virtual machines, where data can be forensically examined away from the production IT system. “Ransomware attacks will vary in nature, with the level of infection dictating the recovery strategy being used. Organizations can utilize modern backup infrastructure to restore rapidly in certain situations but must ensure ransomware is eradicated and the threat vector is eliminated or risk reinfection,” Gartner notes in a report.
The company also advises that an immutable copy of backup data be placed in an “air-gapped” location closed to all outside networks.