gpart: can not add MBR partitions with "gpart add -t mbr"

Warren Block wblock at
Wed Jun 19 16:02:28 UTC 2013

On Tue, 18 Jun 2013, O. Hartmann wrote:

> Having a 1TB disk with a MBR partition layout created successfully with
> "gpart create -s MBR ada4", which is shown as
> Geom name: ada4
> modified: false
> state: OK
> fwheads: 16
> fwsectors: 63
> last: 1953525167
> first: 63
> entries: 4
> scheme: MBR
> Consumers:
> 1. Name: ada4
>   Mediasize: 1000204886016 (931G)
>   Sectorsize: 512
>   Mode: r0w0e0
> it is impossible for me to create a partition with
> gpart add -t mbr ada4
> as it can be read in the manpage of gpart.

I can't find that in 9-stable or -head.  If it's a literal example, 
please point it out and I'll fix it.

> Whatever I do, I receive a
> useless error from gpart
> gpart: Invalid argument
> with no further information.
> In kernel, I already added GEOM_MBR. geom_part_mbr and geom_part_ldm
> kernel modules are then already loaded.
> I tried to figure out what's going wrong but this seems highly
> enigmatic.
> What am I doing wrong?

"mbr" is partitioning scheme, not a partition type.  Common MBR 
partition types that gpart knows by name are freebsd, freebsd-ufs, 
freebsd-zfs, ntfs, no doubt lots of others but offhand I don't know 
where to get the whole list.

Examples shown here (MBR in the second half):

Numbers can also be used for partition types by prefixing them with an 
exclamation point, but that must be escaped to keep the shell from 
interpreting it:

   gpart add -t \!12 -s1G ada0

That would add a "FAT32X/LBA" partition.  There's a list of values here:

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