No /dev/urandom

[Hein van den Heuvel]

Interesting...

>> Well Dennis if you read what i want to do,

Dennis read what you want to do, but is one step ahead of you, which you fail to see/accept.
He, like most of the folks here reading your question, realizes that you are on a wrong tangent and wants to help you with the true problem behind the question.

>> Writing zeros do destroy the data on the disk.

Then you should just use /dev/zero and let'r rip. By writting chunks of zeroes at random place you may will destroy some data, but not all. That will make it harder to figure out what was on the disk, bight might not make it impossible.

There are many, many prior topics on 'destroying' data on a disk. Just google.

>> If you not going to help me out then stop moaning what other people saying as they are trying to help me out unlike you.

He is trying to help better than the others by addressing the real problem vs the perceived problem.

>> All I want is to write zero randomly across the disk

Then you would need to randomly change the optional 'oseek' argument value for the dd command to create an 'Output Seek'.

The 'if' argument is the Input File and by providing /dev/zero this will give an infinited stream of buffers of zeroes, where a /dev/random would provide a stream of buffers of random data... but the dd command will just write those out one after the other, not in a random place. You'd be getting random data in a predictable place.

Cheers,
Hein.

[OldSchool]

"But i assume that the /dev/urandom will write 0's all over the disk randomly ( Like a butterfly effect) than from beging to end..."

nope. its going to write a random number from beginning to end, not 0's randomly across the disk.

as noted in the other thread you noted, pvcreate + multiple passes are a viable alternative.