Follow these guidelines to maximize data protection and security:
Back up important data using devices such as external hard drives or USB storage devices. Store the backed-up data in a second, off-site, secure location.
Use data encryption software to keep confidential information on hard drives secure.
When disposing of an old hard drive, physically destroy the drive or completely erase all the data on the drive. Information can still be recovered from a drive after files are deleted or the drive has been reformatted. Deleting the files or reformatting the drive removes only the address tables on the drive. Use disk wiping software to completely erase all data on a drive.
Hard drives are often used to store sensitive information. To protect this information from unauthorized disclosure, hard drives should be sanitized prior to being reused, decommissioned, or disposed.
Use disk-wiping tools such as the Oracle Solaris format(1M) command to completely erase all data from the disk drive. Alternatively, you can use physical degaussing tools, if appropriate and available.
In some cases, the information contained on the hard drives is of such sensitivity that the only proper sanitation method is physical destruction of the hard drive by means of pulverization or incineration.
Organizations are strongly encouraged to refer to their data protection policies to determine the most appropriate method to sanitize hard drives.
If required, take advantage of Oracle's Customer Data and Device Retention Service: http://www.oracle.com/us/support/library/data-retention-ds-405152.pdf
Caution - Disk-wiping software might not be able to delete some data on modern hard drives, especially solid state drives (SSDs), due to the way that they manage data access.