Unallocating the blocks would be just an update to the spacemap metadata and would be very quick. The zero process takes a considerable amount of time and constitutes lots of disk reads\writes (LEDs are very busy).
From what I can tell, it's an outright 'zeroing' process where every block is overwritten... albeit not to the level that disk sanitize does (8 overwrites I believe??)
-----Original Message----- From: owner-toasters@mathworks.com [mailto:owner-toasters@mathworks.com] On Behalf Of Blake Golliher Sent: Saturday, February 18, 2006 1:15 AM To: Adrian Ulrich Cc: toasters@mathworks.com Subject: Re: wiping disks on an old F230
Or maybe, it just unallocated those blocks, and says "that data there? just ignore it". Which to me is more likely.
-Blake
On 2/17/06, Adrian Ulrich toaster@blinkenlights.ch wrote:
I don't belive spares_zero acutally overwrites data,
It does.
Proof: Adding a 'zeroed-out' disk to an aggr/trad_volume takes just a few seconds.
Why? -> Because the filer *knows* that the disk is filled with \0's
so
the parity-disk does not have to care about the new disk.