Solved. Re: Dualboot and ZFS

Warren Block wblock at
Fri Mar 23 17:42:47 UTC 2018

On Fri, 23 Mar 2018, Victor Sudakov wrote:

> Warren Block wrote:
>>>> On Mon, 19 Mar 2018, Victor Sudakov wrote:
>>>>> sysctl kern.geom.debugflags=0x10
>>>> Please reconsider doing this without it being required.  It means "allow
>>>> destroying mounted partitions" and is usually not necessary.
>>> It is recommended, or even required ("must") by the zfsboot(8) man page:
>> The vagueness here is from the "If the drive is currently in use".  It
>> could easily be replaced with "If the user wants to destroy data from a
>> drive that is currently being used".
> In my script, the ${DISK} is supposed to be a new disk onto which a
> system is installed (cloned actually), so any data thereon would be
> destroyed anyway.
>> I would argue that we should
>> remove or rewrite that, as it is misleading.  Overwriting a drive that
>> is "in use" is generally exactly the opposite of what people want.
> I'm afraid your concern is a bit misdirected. If you can suggest a way
> to install zfsboot without dd, and document it in zfsboot(8) then of course
> kern.geom.debugflags=0x10 is better avoided.

That's the thing, dd should work without the debugflags setting.  If it 
does not, it means you are trying to overwrite something in use.

More information about the freebsd-questions mailing list