recovery problem

[Storm Shadow]

we have same setup, but with 4 cameras and 2 TB Drive,
so we get 30 days instead of 15 days.As niculaita's stated you cant recover the videos.We had a incident and manufacture said we couldn't recover the files.Best option is to have a NAS with swappable drives so you can have like half a year before deleting.

[Kerlingen]

All of those "recover" or "undelete" tools just have a chance of recovering anything if the files still exist undamaged on the HDD and just the directory entries pointing to them have been deleted or damaged. If the files have been overwritten by new files it's impossible to recover anything.

Overwriting files 6 or 31 or 35 or whatever times with special patterns to make them unrecoverable is just an urban legend. It doesn't matter if you write 0-bits, 1-bits or random bits, as soon as the data is overwritten just one time it's unrecoverable and lost forever.

This is true for all normal hard disks and floppy disks. Even on tape drives commonly used when the "multiple overwrite theory" was created nobody was ever able to recover a single bit of data after a single overwrite.

On a SSD/Flash drive some of the "overwritten" data might still exist for a few minutes until the drive's firmware has enough free time to actually reset the memory cells. But in this situation nothing is "overwritten", the firmware just uses some other memory cells to save the new data before deleting the old data.