The four new Continuous Data Protection (CDP) models, available Dec. 15, replace the four original models which the company is no longer selling. SonicWall has not set formal end-of-life details for them.

Two of the new boxes are designed for small and midsize businesses with 400GB of storage. The other two, with up to 4.25TB of RAID 5 storage, are designed for central corporate sites to back up smaller appliances. They can also be used by value-added resellers as part of a backup-in-the-cloud service, SonicWall says.

The old CDP models stored 160GB to 600GB.

CDP devices can restore data from block-level changes to entire hard drives, and the company claims end users can make the fixes themselves without the intervention of IT administrators.

CDP client software runs on each machine to be backed up. It continuously backs up changes to the file system. Since buying the technology with the purchase of  in 2005, SonicWall has rewritten the firmware for the appliances to harden it.