2015-10-07 0:58 GMT+08:00 Ted Unangst <t...@tedunangst.com>:
>
> the disklabel is the second sector of the openbsd part of the disk.
>
> *3: A6 0 1 2 - 243200 254 63 [ 64: 3907024001 ] OpenBSD
>
> so, if you overwrite sector 65, you will overwrite disklabel. normally the
> 'a'
> partition overlaps the disklabel, but you made 'e' first.
>
Ugh, ok - just to settle this one forever I hope, four brief Q:s:
1) Does this mean that on an ordinary disk (where the "a" partition is the
disk's first partition, and starts at the offset autogenerated as default
option by the "disklabel" tool), the start of the "a" partition" actually
overlaps with disklabel-internal data?
What's the proper approach here - I thought partitions' contents were
expected to be completely separate from disklabel-internal data and was
completely unaware that the "disklabel" tool's default behavior is to
autogenerate offsets (and sizes?) that overlap those.
2) Does this mean that for my partitions never to overlap the disklabel, I
must ensure that they never start at a sector or byte offset lower than a
given one, if so which one?
(Disklabels are constant-size so this is a constant that can be
learned?)
3) Is this some how a feature ("and not a bug") so that some frequently
used tools actually rely on this overlapping between disklabel sectors and
partition-a-sectors, for instance "installboot"?
4) If this is documented anywhere feel free to mention.
Also sorry for the fuss but me and some others found it surprising.
