How to mirror the FreeBSD OS on two disks

[Wojciech Puchar]

>>> If that last block is already part of an MBR partition, the more strict 
>>> checking stops booting in 9.0.
>> 
>> not making MBR partition would not make problems.
>
> There's no guarantee that bsdlabel checking won't be made more strict. No 
> matter what type of partitioning scheme, the metadata should not be
> inside the data area.
>
gmirror puts it's metadata at the end of disk.
bsdlabel is at the beginning. what a problem?