Mailinglist Archive: opensuse (1786 mails)

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Re: [opensuse] Re: SSD in openSUSE.
On Wed, Nov 23, 2011 at 7:19 PM, Joachim Schrod <jschrod@xxxxxxx> wrote:
Greg Freemyer wrote:
On Tue, Nov 22, 2011 at 7:44 PM, Joachim Schrod <jschrod@xxxxxxx> wrote:
If you can afford it, don't use 15% of the disk. To get this free
space, use secure erase to reset the disk's firmware notion of what
you're using, and then don't allocate 15% of the disk during
partitioning.

Undocumented feature time.  First secure erase is not always
implemented on SSDs, so don't trust it.

That's new for me, I haven't found this information via Google.

Can you give more information, maybe perhaps some links, about that
issue? I've always thought I can rely on secure erase via hdparm,
while respecting the frozen issue/state.

My knowledge is under NDA. I will just say that for a while a major
manufacturer returned success for secure erase commands, but if you
disassembled (desoldered) the chips and took a look, data was still
present.

For the record:
 -- My SSD is a Micron Crucial RealSSD C300, i.e., a
   Indilinx-based drive,
 -- I bought it with a Thinkpad T420s. It was secured against
   erasing. I.e., "hdparm -I /dev/sda" explained it's frozen.
 -- So, I booted the Thinkpad from a SUSE DVD, and removed the
   hard disk while running and inserted it again. (This removes
   frozennes, AFAIK.)
 -- To check:
   hdparm --user-master u --security-set-pass xyzzy /dev/sda
   and then "hdparm -I /dev/sda" showed that the master pwd
   is "enabled".
 -- Then "hdparm --user-master u --security-erase xyzzy /dev/sda"
   Afterwards check, master password is not enabled any more.

As far as I've read reports on the Net; this kind of actions
(checking that secure erase is enabled and then really doing it) is
supported by Linus.

Do you have differing information?

Again, I'm talking about SSDs that have faulty implementations. ie.
Bugs in their firmware. So by all appearances it works, but if you
dig under the covers it doesn't.

The reality is the SSD firmware is far, far more complex than rotating
disks, so there is a lot more that can go wrong.

       Joachim

Greg
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