topic Re: Data shredder in Operating System - HP-UX

Data shredder

kavanagh_1 — Tue, 07 Nov 2006 10:50:58 GMT

Can anyone advise on a tool to securely delete data stored on an EVA ? OS=hpux

David

Re: Data shredder

James R. Ferguson — Tue, 07 Nov 2006 10:53:51 GMT

Hi David:

One solution is to write zeros or a random pattern at least once over the disk. This is a "reasonable" destruction of data.

# dd if=/dev/zeros of=/dev/rdsk/cXtYdZ bs=1024k

or:

# dd if=/dev/urandom of=dev/rdsk/CxtYdZ bs=1024k

Note the use of the raw disk device to circumvent the LVM layer, and the use of a large blocksize for fast I/O.

Regards!

...JRF...

Re: Data shredder

Peter Godron — Tue, 07 Nov 2006 11:07:29 GMT

David,
please see previous posts:
http://forums1.itrc.hp.com/service/forums/questionanswer.do?threadId=972440
http://forums1.itrc.hp.com/service/forums/questionanswer.do?threadId=458247
http://forums1.itrc.hp.com/service/forums/questionanswer.do?threadId=870349

Main answers:
mediainit (slow) and dd

Re: Data shredder

kavanagh_1 — Tue, 07 Nov 2006 11:15:34 GMT

Hi James,

Thanks for your very quick reply.

I have used the command: "# dd if=/dev/zero of=/dev/rdsk/cXtYdZ bs=1024k" before.

The requirement is to ensure data is securely deleted during decommissioning of an EVA previously used for a trading system.

The HP XP12000 now has a product called the "HP StorageWorks XP Data Shredder" which offers

1) Overwrites data volumes up to eight times.

2) User selectable overwrite patterns:
The customer can choose his own overwrite patterns or else he can choose a random overwrite pattern.
etc

Do you know of any tool that could give a more thorough deletion ?

Regards

David

Re: Data shredder

James R. Ferguson — Tue, 07 Nov 2006 11:27:37 GMT

Hi (again) David:

Certainly, multiple random overwrites are superior to one pass. Sophisticated techniques allow data recovery even after multiple writes have occured. You have to decide on how sensitive your data is and how likely someone else might want to attempt to recover it.

If you are really interested in data distruction, physical shredding of the media (or an acid etching) is required. There are companies that perform this kind of service. Google the web if you need.

Regards!

...JRF...

Re: Data shredder

A. Clay Stephenson — Tue, 07 Nov 2006 11:27:53 GMT

One tool would be a sledge hammer; another might involve explosives. In any event, 8 passes of random data should more than suffice. To add another layer, once the random i/o operation is completed then randomly rearrange the disks within the array (or even between arrays).

Re: Data shredder

James R. Ferguson — Tue, 07 Nov 2006 13:12:03 GMT

Hi David:

Here's a simple recipe that will guarantee no one will read your data :-))

http://driveslag.eecue.com/

Regards!

...JRF...

Re: Data shredder

kavanagh_1 — Tue, 14 Nov 2006 15:07:36 GMT

Just ordering a furnace!!

Not really. Now writing a script following the recommendations.

Many thanks