scrubbing scsi disks using os hpux 11.0

[ernest tamura]

We will be replacing hp9000 k370 servers and need
to scrub the scsi drives before disposing of the
servers. Is there an HP command that does this or a freeware software that I can obtain? Thank you.

[Jeff Schussele]

Hi ernest,

The mediainit command is the "built-in" command to do this, but a short dd-constructed scipt to write a series of 1s & 0s - randomally is much better.
Just search the forum for "disk scrubbing" to get details.

Rgds,
Jeff

[Charles Harris]

I always favour nohup'ing dd if=/dev/random of=/disk although it can take ages and might
not complete if it's your root disks....



Just a thought!

-=ChaZ=-

[Indira Aramandla · Accepted solution]

Hi Ernest,

We had decomissioned K360 Class Servers two months ago. This is what we did to clean the disks.

There should be a zero executable in /dev that will replace the disk data with 0's and 1's.

If you do not have the zero in /dev then create it as follows.

cd /dev
mknod zero c 3 0x000003
chown bin:sys zero
chmod 666 zero

Then Deactivate volume groups

vgchange -a n /dev/vgxx

Then do this

dd if = /dev/zero of= /dev/dsk/c0t0d0 &

do this for all the disks

Indira A

[Florian Heigl (new acc)]

If a simple wipe is enough, use a dd from /dev/zero, if not (government or data from human ressources, customer data), things get complicated on hp-ux.

basically the ideal way (recommended by the german security center BSI at least) is a moving pattern like
11111111
01111111
10111111
11011111
11101111
11110111
11111011
11111110
written on to every disk block, which will ensure that even companies like ontrack will bite their teeth on recovering
the data, but I myself can't translate that into a hp-ux executable.

A compromise would be three runs using both /dev/zero and /dev/urandom.

[Donald C Nelson]

Would writing a file to the disk device perform the same function as the dd command. For example:

cp /stand/vmunix /dev/dsk/c?t?d? or do I have to use the zero file?

[A. Clay Stephenson]

The simple cp of /stand/vmunix is not nearly as good because it would only write blocks until the source file is exhausted. The mainder of the disk would then be left unchanged. Reading from /dev/zero or /dev/random supplies an infinite source of input and the dd terminates when the output device indicates a write error (end of file).

[TwoProc]

Florian (congrats btw) - where to get /dev/random? I don't see it...

[Florian Heigl (new acc)]

It's not there by default on 11.00 - my bad :)

You only have to use
mknod /dev/zero c 3 4
to create it.
the site I looked it up again at contained the word 'unsupported', but I think for wiping disks one can live with that.

[Florian Heigl (new acc)]

...and if I had kept on reading I would have read the following years ago:

"Note, filling a file with zeroes is not a secure way to wipe file data from
disk. For this, you must use a utility such as 'shred', which is part of
the GNU fileutils package."