Continuous Data Protection: Guarding Against Data Loss

An ‘undo’ button for unintended changes in your data

What is Continuous Data Protection?

What is Continuous Data Protection (CDP)Continuous Data Protection (CDP) is a backup and recovery technique that replicates and time stamps every incremental change to critical dataset. In the event of data corruption from logic errors, user mistakes or malware, one can roll back to the specific point in time before the undesired update occurred. Operations may then be resumed as if the problem never happened.

DataCore SANsymphony software-defined storage solution leverages built-in CDP functionality to record every update to a volume in a separate location and time stamp it. Unlike periodic snapshots, it is fully automated and happens continuously in real time. This approach highlights the continuous data protection advantages, complementing your backup solution without being a replacement for it.

CDP Feature Highlights

  • Protect against damage from ransomware, malware and other sources of data corruption
  • Rollback to restore a volume to an arbitrary point-in-time state within a 14-day time frame
  • Generate known-good restore points
  • Logs and timestamps all I/Os to the selected virtual disks
  • Operates independent of operating system or applications
  • No need to quiesce or interrupt applications
  • No host agents required
  • Easy to enable protection and create rollback volumes

How Continuous Data Protection Works

CDP records every write I/O (or change), with a corresponding timestamp, that occurs against a protected volume. With continuous data protection, software like SANsymphony, a rollback volume can be created representing any point-in-time just before the undesired event occurred. The rollback volume is then mapped to the original application server or a different one.

For example, consider a virus causing damage to your data at 2:41:36 PM: just return to the status at 2:41:35 PM with a rollback volume and serve it back to the original application server. As another example, consider a user deleting a file at 3:15 PM: let the administrator roll back to a point in time before it was deleted and restore the file from that copy.

Similar to snapshot requests, one can generate periodic CDP Rollback Volumes at known-good restore points by scripting a call to a PowerShell cmdlet each time an application has been quiesced and the caches have been flushed to storage.

How Continuous Data Protection Works
As data is written to the protected production volume, a copy of each write I/O is copied to the designated CDP storage buffer pool. A rollback volume can be created based on the data that resides in the CDP buffer pool at a specified time.
RPO RTO RTA diagram
The figure above highlights the differences in RPO and RTO values between storage backup, snapshot, and CDP with SANsymphony

CDP Ensures Lower RPO Than Traditional Backup and Snapshots

Because traditional backup is done on a daily basis and snapshots are taken every few hours, the recovery point objective (RPO) with these operations is much higher than CDP. Since CDP technology can restore the data in the affected volume to just right before the event of disruption, RPO for CDP is close to zero. Recovery time objective (RTO) values are also lower for CDP when compared to storage backup and snapshots.

“CDP is an important feature for avoiding data loss in the event of ransomware attacks. You need more storage capacity, however, you get the possibility to return at any time and use the data saved up to that point. The recovery is much faster than with a classic restore.”

Christian Baldauf Architect at MightyCare Solutions GmbH

Understanding the Difference Between True CDP and Near-CDP

True CDP is the process where data copies are captured every time there is a data change at source and is a continuous incremental recording process. True CDP offers a recovery point objective (RPO) of close to zero, which means there is no data loss.

Near-CDP, as the name indicates, is a near-continuous process where there is a pre-defined time interval for snapshotting the data. Near-CDP offers an RPO of however-often-you-are-taking-a-snapshot (typically one hour).

DataCore SANsymphony offers true CDP as part of its built-in data services, which can be used in tandem with a traditional backup solution to prevent data loss and aid in disaster recovery.

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