What is Continuous Data Protection?
In its simplest form, Continuous Data Protection, or CDP, is instantaneous backup of any file changes that occur. There are different levels of CDP, however, and each level has tradeoffs.
Better than backup. Traditional backup occurs on set schedules and leaves a window of time where newly created files or modified files are not protected. Continuous Data Protection works in the background to monitor file changes and protect those files immediately.
In extreme cases, a business may need hardware CDP, but these systems require setup and ongoing monitoring to ensure proper operation. In the case of hardware CDP, any file modification that occurs to a file on disk is also mirrored onto an alternate disk or backup media. Similar to RAID, these hardware systems respond in milliseconds to ensure the smallest possible loss window.
Software Continuous Data Protection (Software CDP) backs up files that have changed almost instantaneously. With a small number of files to copy at a given time, the CDP operation is not noticeable and provides optimal protection for data files that change throughout the day. In this case, the software is tightly integrated with the Windows OS to ensure that any file written to one hard disk drive is also written to an alternate hard disk drive. While there may be a lag in time for the individual files to be copied to the alternate hard disk drive, the loss window is small, typically on the order of a second or two.
Near Continuous Data Protection (Near CDP) backs up files that have changed within a few moments. With a small queue of files to copy at a given time, the CDP operation is not typically noticeable. In some implementations, this operation is suspended during periods of user activity to provide optimal protection for data files while yielding computer resources to the current work activity. The advantage here is that no backup operation will delay the current activity of the computer. While there may be a lag in time for the individual files to be copied to the alternate hard disk drive, the loss window is relatively small, typically on the order of a 30 seconds.