incremental disk wipe?

[Tony Arnold]

Rikona,

On 07/03/15 14:25, rikona wrote:
> Hello Rashkae,
> 
> Friday, March 6, 2015, 11:22:38 PM, Rashkae wrote:
> 
>> On 15-03-07 01:09 AM, rikona wrote:
>>> I was checking the timing of securely wiping large disks - looks like
>>> it takes a looooong time. Is there a way to do this in smaller
>>> 'chunks', that might complete in an hour or so, eventually filling up
>>> the entire disk? I'm not hiding plots from NSA, so I don't need
>>> extreme security - just enough to discourage easy-tech snoops. :-))
>>>
>> dd if=/dev/zero of=/dev/sdX bs=4M
> 
>> This will be as fast as you can go, but it will still take a modern 
>> large hard drive several hours to finish.  But a drive that writes 
>> 200MB/s still only writes 200MB/s... the drive can't multiple chunks 
>> simultaneously.
> 
> Thanks to you and others for the replies. I wasn't thinking of
> multiple chunks simultaneously - rather sequentially. Let's say I'll
> be away from the comp for 30 min or so. How can I keep it busy for
> JUST 30 min - no more, to do *part* of the wipe? Then, later, do
> another 30 min, eventually wiping the entire disk?

Why not run the dd command as suggested in this thread, but in the
background with a nice value of 19. That way the process will run when
there is little else for the processor to do, so it should not affect
the day to day running.

I'm not sure what you are trying to achieve. You say wiping takes a long
time, but doing it in chunks or as I've suggested above means it will
take even longer?

BTW, writing zeroes to the disk using dd will definitely prevent the
'easy-tech' snoops from recovering your data.

Regards,
Tony.
-- 
Tony Arnold, IT Security Analyst, University of Manchester.
T: +44 (0) 161 275 6093, F: +44 (0) 705 344 3082,
M: +44 (0) 773 330 0039, E: tony.arnold at manchester.ac.uk