[lug] Identical UUID for MD devices?

[stimits at comcast.net]

I am curious if the dd trick applies equally to old BIOS style partitions and GPT partitions?
 
----- Original Message -----From: BC <bcarr at purgatoire.org>To: Boulder (Colorado) Linux Users Group -- General Mailing List <lug at lug.boulder.co.us>Sent: Thu, 08 Feb 2018 20:06:27 -0000 (UTC)Subject: Re: [lug] Identical UUID for MD devices?



On 2/8/2018 12:59 PM, Rob Nagler wrote:




As soon as I shredded enough of the disk (probably first few blocks is enough), the raid1 UUIDs disappeared from lsblk output.






The drive references are BSD-style, but the technique ought to be the same in Linux.  I run these on all drives I want to freshen before using for anything:

 Here's the magic incantation for wiping the beginnning & end of your disk(s), replace adaX with your disk/device:

     |# dd if=/dev/zero of=/dev/adaX bs=1m count=5

    |# dd if=/dev/zero of=/dev/adaX bs=1m oseek=`diskinfo adaX | awk '{print int($3 / (1024*1024)) - 4;}'`

 repeat for all the drives you desire to wipe.

 Turns out that some clever OSes and drive utils write metadata to the beginning and end of each drive.

 I purloined this from the internet...

 Bucky


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