Disk sanitization is the process of physically obliterating data by overwriting disks with specified byte patterns or random data so that recovery of the original data becomes impossible. You use the disk sanitize command if you want to ensure that no one can recover the data on the disks.
The disk sanitize command uses three successive default or user-specified byte overwrite patterns for up to seven cycles per operation. Depending on the disk capacity, the patterns, and the number of cycles, the process can take several hours. Sanitization runs in the background. You can start, stop, and display the status of the sanitization process.
After you enter the disk sanitize start command, Data ONTAP begins the sanitization process on each of the specified disks. The process consists of a disk format operation, followed by the specified overwrite patterns repeated for the specified number of cycles.
If the sanitization process is interrupted by power failure, system panic, or a user-invoked disk sanitize abort command, the disk sanitize command must be re-invoked and the process repeated from the beginning in order for the sanitization to take place.
When the sanitization process is complete, the specified disks are in a sanitized state. You return the sanitized disks to the spare disk pool with the disk sanitize release command.