Re: gpart destroy, in depth

From: Warner Losh <>
Date: Tue, 11 Apr 2023 13:24:57 UTC
It writes zeros to the partition table.


On Tue, Apr 11, 2023, 7:13 AM Graham Perrin <>

> Please: what, exactly, occurs when a partition table is destroyed by
> gpart(8)?
> Background: a customer was 100% certain that no data was required from a
> hard disk in an iMac that will be disposed of. I booted from a USB drive
> with FreeBSD 14.0-CURRENT, then lazily ran gpart destroy for the
> internal disk (probably ada0). A few hours later, the customer realised
> that the disk probably held a few years' worth of important emails.
> I don't intend to attempt recovery, or recreation of the partition
> table, but I'd like to provide enough technical information for a third
> party to advise the customer whether doing so will be economically viable.
> (I see files such as lib/geom/part/geom_part.c and
> sys/geom/part/g_part.c, but I have no idea how to interpret them.)
> Thanks
> <
> >
> <>