`gpart show` and secondary GPT header

[James R. Van Artsdalen]

Marcel Moolenaar wrote:
> In any case: the primary and secondary GPT headers
> and tables are in fact on the disk. They're there,
> trust me :-)

Unless you're using a Silicon Image 3124 controller :-(

FYI - the option ROM on this card appears to clobber the secondary GPT
table.  Moving disks to a 3124 results in this:

Jun 13 06:31:42 bigback kernel: GEOM: ad4: the secondary GPT table is
corrupt or invalid.
Jun 13 06:31:42 bigback kernel: GEOM: ad4: using the primary only --
recovery suggested.
Jun 13 06:31:42 bigback kernel: GEOM: ad12: the secondary GPT table is
corrupt or invalid.
Jun 13 06:31:42 bigback kernel: GEOM: ad12: using the primary only --
recovery suggested.

Not our fault  - just thought I'd mention it in case it comes up again,
or if someone searches for that error message.

PS. The man page might make a mention of what "recovery" is if there's
some way other than dd(1) to do it.