[CentOS] erasing a disk

Mon Sep 14 20:14:44 UTC 2020
david <david at daku.org>


I've encountered situations where I want to reuse a hard-drive.  I do 
not want to preserve anything on the drive, and I'm not concerned 
about 'securely erasing' old content.  I just want to be able to 
define it as an Physical Volume (in a logical volume set), or make it 
a ZFS disk, or sometimes make it a simple EXT3, ExFAT or NTFS 
disk.  However, old 'signatures' get in the way and Linux sometimes 
refuses to let me proceed.  I know that a fool-proof solution is to 
use the "dd if=/dev/zero bs=32768 oflag=direct" on the disk, but when 
we're talking USB-connected hard drives of 8 TB, that's an operation 
that can take days.

The disk in question might even have been corrupted.  This would make 
using 'zpool destroy' to clear out a ZFS disk, or

I've tried erasing the first megabyte of the disk, but there are ZFS 
or LVM structures that get in the way.  So, does anyone have an 
efficient way to erase structures from a disk such that it can be reused?

Something like
   -erase first N blocks (block defined as 4096)
   - Erase <number> blocks starting at block <number>
   - erase last <number> blocks

At least such an algorithm would be quicker than erasing 8 TB of data.