Quicky about a DD command in linux in recovery mode.

[Tal]

Anyone know if when I run a "dd if=/dev/random of=/dev/sda" if I should see something after I hit enter.
It doesn't go right back to the shell prompt, but I can't tell if it's doing anything. It's a scsi dive obviously, and the HD light doesn't appear to be doing anything. Did I run the command wrong? Thanks, -Tal

 

[Chaotic42]

I think that dd has a verbose switch.

Why are you doing this, by the way?

 

[Tal]

Selling a box on FS/FT and am paranoid... 😛

I'm not that worried, but I just wanted to do a quick wipe.

Can't find a verbose option in dd--help and it said o outputed when I Ctrl-C'd the one that was running.

Any other relatively quick (by tommorrow morning) tools to wipe a 18GB SCSI drive?

 

[Chaotic42]

Originally posted by: Tal
Selling a box on FS/FT and am paranoid... 😛

I'm not that worried, but I just wanted to do a quick wipe.

Ah. 😉

Try:

"dd -v if=/dev/random of=/dev/sda"

 

[Tal]

nope. -v is unrecognized.

 

[Chaotic42]

Originally posted by: Tal
nope. -v is unrecognized.

Well, try "info dd" or "man dd" to find out. There has to be some kind of verbosity switch.

 

[Tal]

If I create a partition and mount it, I can write a GIANT ASS 18GB file to it it looks like. Maybe that's enough...

Man and info don't work as I'm in the recovery mode.

 

[Chaotic42]

Originally posted by: Tal
If I create a partition and mount it, I can write a GIANT ASS 18GB file to it it looks like. Maybe that's enough...

Man and info don't work as I'm in the recovery mode.

Ah, I wasn't sure if they'd work or not.

Manpage link

 

[Heisenberg]

Here is a linux-based boot disk to wipe hard drives.

 

[manly]

That's not going to work; you're assuming dd will dump random bits onto that drive indefinitely until it's full.

If you're being paranoid, you need a 7-pass DoD grade disk scrubber anyhow.

 

[Tal]

Originally posted by: manly
That's not going to work; you're assuming dd will dump random bits onto that drive indefinitely until it's full.

If you're being paranoid, you need a 7-pass DoD grade disk scrubber anyhow.

Like "Scrub"??

 

[manly]

Originally posted by: Tal

Originally posted by: manly
That's not going to work; you're assuming dd will dump random bits onto that drive indefinitely until it's full.

If you're being paranoid, you need a 7-pass DoD grade disk scrubber anyhow.

Like "Scrub"??

Like Heisenberg's recommendation.

 

[Tal]

Thanks everyone. I'm trying Dban now.

 

[Nothinman]

That's not going to work; you're assuming dd will dump random bits onto that drive indefinitely until it's full.

And unless I'm reading that incorrectly, that's what will happen.

 

[Tal]

DBAN seemed to work great! Thanks for the input everyone!

 

[manly]

Originally posted by: Nothinman

That's not going to work; you're assuming dd will dump random bits onto that drive indefinitely until it's full.

And unless I'm reading that incorrectly, that's what will happen.

I believe you'd have to at least instruct dd to write out the number of bytes necessary (see the bs and count flags), and it would still take a god-awful amount of time for the random bit bucket to fill the drive if I'm not mistaken.

 

[Nothinman]

I believe you'd have to at least instruct dd to write out the number of bytes necessary (see the bs and count flags), and it would still take a god-awful amount of time for the random bit bucket to fill the drive if I'm not mistaken.

No, with no bs or count options it goes forever or until a read or write error occurs. But yes it would take a really long time since /dev/random blocks until randomness can be generated, /dev/urandom would be better but would still take a while.

 

[drag]

Originally posted by: Nothinman

I believe you'd have to at least instruct dd to write out the number of bytes necessary (see the bs and count flags), and it would still take a god-awful amount of time for the random bit bucket to fill the drive if I'm not mistaken.

No, with no bs or count options it goes forever or until a read or write error occurs. But yes it would take a really long time since /dev/random blocks until randomness can be generated, /dev/urandom would be better but would still take a while.

Exactly. dd if=urandom of=/dev/sda will write until the disk is full. Once it is full it will give you a error because it ran out of space.

And it will take a while because your actually writing a file big enough to fill the entire disk. If you have a 30gig disk your making a 30 gig file of gibberish.

I've done this myself a few times to help correct errors on disks....