Sans Digital
VSA NVR
It all starts with IP cameras that record the videos. Once the video sends to the VSA NVR product, it will automatically generate lower resolution copy for preview, allowing quick preview and instant search. Depending on the situation and policy, it can keep the original high resolution files to internal storage, or move to different units for backup, or even move to different offline media for low cost retention. All process are done automatically.
http://www.sansdigital.com/vsa-series.html