Re: [gentoo-user] Securely deletion of an HDD

[Marc Joliet <marcec@gmx.de>]

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Am Sun, 12 Jul 2015 18:32:39 +0200
schrieb Volker Armin Hemmann <volkerarmin@googlemail.com>:

> Am 12.07.2015 um 14:35 schrieb Marc Joliet:
> > Hi,
> >
> > I have to failed drives that I want to give away for recycling purposes, but
> > want to be sure to properly clear them first.  They used be part of a btrfs
> > RAID10 array, but needed to be replaced (with "btrfs replace").  (In the
> > meantime I converted the array to RAID1 with only two drives.)
> >
> > My question is how precisely the disks should be cleared.  From various sources
> > I know that overwriting them with random data a few times is enough to render
> > old versions of data unreadable.  I'm guessing 3 times ought to be enough, but
> > maybe even that small amount is overly paranoid these days?
> >
> > As to the actual command, I would suspect something like "dd if=/dev/urandom
> > of=/dev/sdx bs=4096" should suffice, and according to
> > https://wiki.archlinux.org/index.php/Random_number_generation#.2Fdev.2Furandom,
> > /dev/urandom ought to be random enough for this task.  Or are cat/cp that much
> > faster?
> >
> > Any thoughts?
> >
> > Greetings
> 
> actually 1 time is enough. With zeros. Or ones. Does not matter at all.

If you look at my initial response to Rich, I already concluded that "one time
is enough", although I'm going to stick with whatever random data shred(1)
produces.

-- 
Marc Joliet
--
"People who think they know everything really annoy those of us who know we
don't" - Bjarne Stroustrup

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