Hey guys,

I want to shred/sanitize my SSDs. If it was a normal harddrive I would stick to ShredOS / nwipe, but since SSD’s seem to be a little more complicated, I need your advice.

When reading through some posts in the internet, many people recommend using the software from the manufacturer for sanitizing. Currently I am using the SSD SN850X from Western digital, but I also have a SSD 990 PRO from Samsung. Both manufacturers don’t seem to have a specialized linux-compatible software to perform this kind of action.

How would be your approach to shred your SSD (without physically destroying it)?

~sp3ctre

  • hendrik@palaver.p3x.deEnglish
    9·
    2 hours ago

    Well, in fact it can. That’s “overprovisioning”. The SSD has some amount of reserved space as replacement for bad cells, and maybe to speed things up. So if you overwrite 100% of what you’ve access to on the SSD, you’d still have X amount of data you didn’t catch. But loosely speaking you’re right. If you overwrite the entire SSD and not just files or one partition or something like that, you’d force it to replace most of the content.
    I wouldn’t recommend it, though. There is secure erase, blkdiscard and some nvme format commands which do it the right way. And ‘dd’ is just a method that get’s it about right (though not 100%) in one specific case.

    • 𝕽𝖚𝖆𝖎𝖉𝖍𝖗𝖎𝖌𝖍@midwest.social
      3·
      3 hours ago

      Hum. I read that blkdiscard only marks the blocks (cells?) as empty, and doesn’t change the contents; and that a sophisticated enough lab can still read the bits.

      In particular, the disk has to claim to support “Deterministic read ZEROs after TRIM”; if it doesn’t, you have no guarantee of erasure. Without knowing anything about the make and model, blkdiscard would be categorically less secure.

      Right?

      • hendrik@palaver.p3x.deEnglish
        2·
        2 hours ago

        Yes, thanks. Just invalidating or trimming the memory doesn’t cut it. OP wants it erased so it needs to be one of the proper erase commands. I think blkdiscard also has flags for that, so I believe you could do it with that command as well, if it’s supported by the device and you append the correct options. (zero, secure) I think other commands are easier to use (if supported).

        • 𝕽𝖚𝖆𝖎𝖉𝖍𝖗𝖎𝖌𝖍@midwest.social
          2·
          1 hour ago

          I did read (on the Arch wiki) that blkdiscard -z is identical to dd if=/dev/zero, so that tracks. It’s (blkdiscard) is easier to use. However, given my memory and how infrequently I’ll ever use it, I’ll have forgotten the name of the command by next week. I’ll never forget dd, though, mainly because it’s more general purpose and I use it occasionally.

          OP probably wants blkdiscard -z, though.

          • hendrik@palaver.p3x.deEnglish
            1·
            30 minutes ago

            I’m not sure about that. I think OP wants something like ATA secure erase. That would be hdparm and a bunch of options, and not blkdiscard. Unless they specifically know what they’re doing and what options to pick. And what the controller will do in return.