Mailinglist Archive: opensuse (1786 mails)

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Re: [opensuse] Re: SSD in openSUSE.
On Thu, Nov 24, 2011 at 4:47 AM, Joachim Schrod <jschrod@xxxxxxx> wrote:
Greg Freemyer wrote:
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.

Yes, that I've read. But that was not my use case. My use case is
"SSD firmware uses all sectors for wear levelling after secure
erase". I don't care if the data is still on it.

Does your NDA-knowledge include information about that use case?

Please note that my posted steps include one step to unlock an SSD,
so locked devices are covered.

       Joachim

My NDA knowledge doesn't cover that use case. We were worried about
drive sanitation (getting rid of data.)

But there are rumors of SSDs that immediately return a success upon
receiving a Secure Erase command (ie. less than a second). That seems
pretty hard to believe they were even doing anything with the command.
ie. It takes several seconds to process a full set of trim commands
even from hdparm (which is extremely efficient. See the wiper.sh
script that comes with hdparm. It will invoke hdparm on a few
different filesystems to trim them fully. fstrim is the new
"supported" way, but it is no where near as efficient as how hdparm
does it.)

Greg
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