I have a stack of SATA hard drives that I need to erase.

I have a USB drive dock, a box that a drive can be set into that connects to my computer via USB-3.

I am using DD to write zeros to the raw device, in this case, /dev/sdf.

No matter the actual size of the drive dd stops at about 3 to 7 gb. These are 300 gb to 3 TB drives.

I am not mounting the drives, but I do ensure they are visible to the system with lsblk. To change drives I turn off the dock. The drive then disappears from lsblk. When I insert a different drive and turn the dock back on again /dev/sdf re-appears.

Are all my drives bad? If they are I will need to have them “professionally” destroyed at about $25 a drive.

  • dack
    1·
    2 years ago

    For the vast majority of people, writing zeroes to the disk is good enough. Even nation states and other advanced attackers would need a good amount of luck to get anything useful off a single pass zeroed HDD.

    If you really need more than that, then there are various standards and recommendations for multiple passes of random/zeros/ones. Or just go the destructive route.

    Of course SSDs are a totally different scenario. Writing zeroes is not sufficient or recommended for those. Generally, the secure erase command is the best way. However, this requires trusting that the firmware does that properly. If you don’t trust the firmware, destructive is the only option.