moving to gpart mirroring, one drive at a time

[Edho Arief]

On Fri, Dec 7, 2012 at 12:08 PM, Randy Bush <randy at psg.com> wrote:
> i have an existing old-style glabel gmirror.  a drive, ada0 failed.  we
> inserted a new drive as ada0.  as the old drive is a teensie 80g drive
> and the new is a 500g, we figured to create gm1, dump/restore to it, and
> then swap out the old working 80g for another 500 and mirror away.
>
> so i went to the handbook.  20.4.3 Creating a Mirror with an Existing
> Drive does not seem appropriate as it assumes no source mirror and equal
> sized drives.
>
> so i figured to do the dance of 20.4.2 Creating a Mirror with Two New
> Disks, but with one disk and then mirror back.  but ...
>
> # gmirror label -v gm1 /dev/ada0
> Metadata value stored on /dev/ada0.
> Done.
>
> # gpart create -s MBR mirror/gm1
> mirror/gm1 created
>
> # gpart show mirror/gm1
> =>       63  976773104  mirror/gm1  MBR  (465G)
>          63  976773104              - free -  (465G)
>
> # gpart create -s BSD mirror/gm1s1
> gpart: arg0 'mirror/gm1s1': Invalid argument
>
> whoopsie.
>
> clue?
>

...create the partition first?

gpart add -t freebsd mirror/gm1