Re: Adding an ioctl to check for disklabel existence

[John Nemeth <jnemeth%cue.bc.ca@localhost>]

On Oct 3,  2:42pm, Rhialto wrote:
} On Wed 02 Oct 2019 at 19:40:01 -0700, John Nemeth wrote:
} >      Cloning disks always presents issues.  However, gpt(8) has
} > grown a "uuid" command to generate new UUIDs.  This was primarily
} > done to help with the cloning problem.  Cloning a disk and then
} > putting two disks with the same UUIDs on the same system is an
} > operator error.
} 
} I was thinking the other day that it might be useful if gpt had a
} subcommand to spit out a script to duplicate the partitioning of a disk,
} but without the "unique" parts. The script would of course be
} hand-editable for any changes one might want to make.

     By "unique" parts, do you mean just the UUIDs, or do you mean
other parts as well?  What would the output look like?

} Such functionality would be the equivalent of using disklabel to get the
} editable text-version of a disklabel from one disk, and applying it to a
} different disk.
} 
} I use this sort of thing if I want to create a backup disk which should
} have the same layout as the original.
} 
} There is "gpt backup", but the manual page mentions "It should not be
} modified" and it contains the guids of the partition which in many cases
} should NOT be duplicated. It also isn't very readable.

     The bit about not modifying it is more of a caution.  You can
modify it if you're careful (checksums are recomputed during
restore).  Obviously if you make an error, it may not be usable
for restore, so you should work with a copy.

}-- End of excerpt from Rhialto