Is it time to dump disklabel and use GPT instead?

Matthew Dillon dillon at
Sun Jul 25 15:37:23 PDT 2010

:DragonFly could really lead the way here amongst the BSDs who all use some
:version of disklabel. Can DF boot from a GPT partition? If so the next
:thing would be teaching it to boot from such a partition without a
:disklabel present.
:For example:
:/boot ... /dev/da0p0
:/ ... /dev/da0p1
:/usr ... /dev/da0p2
:/var ... /dev/da0p3
:and so-on.
:Its simple and elegant and will not confuse everyone who is new the BSDs.

    Well, there are two parts to GPT.  There is the partition table
    standard and then there is the BIOS support.  If you mean booting
    from a GPT compatibility slice without needing the BIOS support
    then it is probably doable.  If you mean using the BIOS support API
    then it gets a lot more difficult.

    However, our 64-bit disklabel tool is far more advanced then our
    gpt tool.  It has uuids, a 64-bit address space, super-sector alignment,
    and no slice limit (though the kernel itself implements some practical
    limits).  FreeBSD has a new gpt suite but I have no idea if their
    partitioning tool was made more convenient (as in throws you into
    vi and lets you loose).

    Going to GPT is more a matter of wanting to support multi-boot.  I
    personally have never been keen on multi-boot setups, I don't see much
    of a point to it other than for playing around.  But if someone wants
    to do the work and can also fix GPT to properly super-sector align
    partitions then go for it!

					Matthew Dillon 
					<dillon at>

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