Wipe Disk Clean

CaptainKirk · 2011-06-16 17:20:05

I need to return a defective hard disk to the store but it has NDA-protected data on it. It's a 1TG disk with about 300G data on it.

I was thinking to reinstall Arch and have it reformat the whole disk as one big partition and I think that's sufficient.

I see one could also use

dd if=/dev/zero of=/dev/hda bs=1M

shred -vfz -n 100 /dev/hda

but those may be overkill. shred looks like it would take a long time anyhow. Perhaps just run it

shred -vfz -n 1 /dev/hda

What is recommended? The data is not super-sensitive (at all) and I don't expect anyone to even have any reason to try to reconstruct it, but anyhow I must of course take reasonable measures to remove the data. I figured reformatting would be the easiest way.

Thanks.

Pierre · 2011-06-16 17:32:15

Reformat wont delete any data. Use dd to fill the whole drive with zeros. Afaik overwriting the drive several times and also using random data is an ancient myth and not needed. (But you'll find a lot information about this using a search engine)

ewaller · 2011-06-16 17:53:00

Pierre wrote:

... Afaik overwriting the drive several times and also using random data is an ancient myth and not needed....

Unless of course it is a requirement imposed (contractual, declassification procedures, etc...) -- Whether or not it is technically valid.

Never-the-less, use the dd command to zero the drive; no one is going to go to the trouble to recover the NDA data after you do that.

As to the dd command: Type the command, but don't hit Enter; sit back; cross your arms; read the command line; think about what you typed; read it again; think some more; then press Enter.
Really.

CaptainKirk · 2011-06-16 18:07:25

ewaller wrote:

As to the dd command: Type the command, but don't hit Enter; sit back; cross your arms; read the command line; think about what you typed; read it again; think some more; then press Enter.
Really.

Thanks. I already CloneZilla'sd the entire drive to a new one (which I am using now), so I'm quite ready to dd the old one.

Thanks for the feedback.

R00KIE · 2011-06-16 21:59:54

You can use only the dd command you posted, with modern disks just one pass is enough to make it close to impossible to recover any meaningful data.

You can also try the Security Erase or Enhanced Security Erase feature provided by the SMART capability of the drive, it will probably be faster than using dd and it will (or should) yield the same result.

stqn · 2011-06-17 07:58:48

CaptainKirk wrote:

Thanks. I already CloneZilla'sd the entire drive to a new one (which I am using now), so I'm quite ready to dd the old one.

I think that what ewaller wanted to say, is that you should check that you didn't swap "if" and "of", and that you wrote the correct device names .

ChoK · 2011-06-17 08:20:41

This can help too http://www.dban.org/

From http://mmlab.itsc.cuhk.edu.hk/eNewsASP/ … A2DC0DC4B/

To prevent leakage of sensitive or important data in the disposal of hard disk, instead of simply deleting files or formatting the hard disk, the better way is to use data wiping tools for data wiping. An open source software – DBAN is recommended for your consideration.
DBAN is a self-contained software which can securely wipe hard disks of most computers. The software will automatically and completely erase all the content that it can detect, which makes it an appropriate utility for bulk and emergency data destruction. It supports various partition formats and data sanitization standards, including DOD 5220.22-M (the data sanitization standards set by the U.S. Department of Defense), Gutmann and PNRG Steam. Moreover, it is an approved product for sanitizing IT equipment of National Aeronautics and Space Administration (NASA).
Please bear in mind that data cannot be recovered after wiping, but the hard disk can still be reused.
For details and DBAN download, visit the DBAN official website: www.dban.org.

graysky · 2011-06-17 08:24:11

https://wiki.archlinux.org/index.php/Securely_Wipe_HDD

ewaller · 2011-06-17 14:57:25

stqn wrote:

CaptainKirk wrote:
Thanks. I already CloneZilla'sd the entire drive to a new one (which I am using now), so I'm quite ready to dd the old one.
I think that what ewaller wanted to say, is that you should check that you didn't swap "if" and "of", and that you wrote the correct device names .

That is precisely what I meant

CaptainKirk · 2011-06-18 19:06:28

Thanks for the advice, and the warnings. I actually physically disconnected the new drive before this operation, that's why I had no concerns.

Anyhow I did it, logged in to Arch. It was fun--I never saw an OS self destruct before.

But now it won't boot. Can you tell me how to fix this?

JUST KIDDING!

Thanks--I used the method in the wiki and it seems to have worked.

stqn · 2011-06-18 19:40:07

Pf

Arch Linux

#1 2011-06-16 17:20:05

Wipe Disk Clean

#2 2011-06-16 17:32:15

Re: Wipe Disk Clean

#3 2011-06-16 17:53:00

Re: Wipe Disk Clean

#4 2011-06-16 18:07:25

Re: Wipe Disk Clean

#5 2011-06-16 21:59:54

Re: Wipe Disk Clean

#6 2011-06-17 07:58:48

Re: Wipe Disk Clean

#7 2011-06-17 08:20:41

Re: Wipe Disk Clean

#8 2011-06-17 08:24:11

Re: Wipe Disk Clean

#9 2011-06-17 14:57:25

Re: Wipe Disk Clean

#10 2011-06-18 19:06:28

Re: Wipe Disk Clean

#11 2011-06-18 19:40:07

Re: Wipe Disk Clean

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