topic Re: scrubbing scsi disks using os hpux 11.0 in Operating System - HP-UX

scrubbing scsi disks using os hpux 11.0

ernest tamura — Tue, 22 Feb 2005 20:29:19 GMT

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.

Re: scrubbing scsi disks using os hpux 11.0

Jeff Schussele — Tue, 22 Feb 2005 20:35:44 GMT

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

Re: scrubbing scsi disks using os hpux 11.0

Charles Harris — Wed, 23 Feb 2005 00:01:54 GMT

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=-

Re: scrubbing scsi disks using os hpux 11.0

Indira Aramandla — Wed, 23 Feb 2005 00:29:21 GMT

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

Re: scrubbing scsi disks using os hpux 11.0

Florian Heigl (new acc) — Wed, 23 Feb 2005 02:38:03 GMT

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.

Re: scrubbing scsi disks using os hpux 11.0

Donald C Nelson — Thu, 24 Feb 2005 09:27:09 GMT

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?

Re: scrubbing scsi disks using os hpux 11.0

A. Clay Stephenson — Thu, 24 Feb 2005 10:36:24 GMT

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).

Re: scrubbing scsi disks using os hpux 11.0

TwoProc — Thu, 24 Feb 2005 10:39:08 GMT

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

Re: scrubbing scsi disks using os hpux 11.0

Florian Heigl (new acc) — Fri, 25 Feb 2005 01:07:07 GMT

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.

Re: scrubbing scsi disks using os hpux 11.0

Florian Heigl (new acc) — Fri, 25 Feb 2005 01:08:21 GMT

...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."

Re: scrubbing scsi disks using os hpux 11.0

Florian Heigl (new acc) — Fri, 25 Feb 2005 04:04:05 GMT

Hmmm, You said /dev/random. I'll go home now, it doesn't seem I've got my brain all mixed up.

http://www.josvisser.nl/hpux11-random/
if You want to give it try?

Re: scrubbing scsi disks using os hpux 11.0

Florian Heigl (new acc) — Fri, 25 Feb 2005 04:22:27 GMT

The hp-ux FAQ also has a short note about random number generation on hp-ux < 11.11

maybe have a look at it.

Re: scrubbing scsi disks using os hpux 11.0

Florian Heigl (new acc) — Thu, 07 Apr 2005 07:40:16 GMT

some guy together a disk wipe c++ program yesterday

http://213.239.200.41/ximig/thread.php?&tid=23460#b829541

!!!I did not yet have time to try it out!!!

Re: scrubbing scsi disks using os hpux 11.0

Lee Harris_5 — Thu, 07 Apr 2005 13:16:47 GMT

If the servers are being decommissioned and then scrapped, you're best (and most fun) bet is to whip the disks out of the machine, and go at them with a hammer...

Keep on hitting them *HARD* until you can pick up the disk shake it, and it sounds like it's full of tiny pieces of broken glass.

No one's recovering that!

Re: scrubbing scsi disks using os hpux 11.0

ernest tamura — Thu, 07 Apr 2005 17:56:06 GMT

Florian, thanks for the url. Lee, love your ultimate solution. The seventh floor gravity test sounds good.