Re: Bug#260763: [powerpc] Problems with logical volume setup during installation
On Fri, Jan 07, 2005 at 05:53:40PM +0100, Michael Schmitz wrote:
> > > There is no such thing as flags for most things in Mac partition tables
> >
> > Parted converts flags to funky partition type names, i think. Not idea, but it
> > works, like said, i think parted is inherently broken on this, but there is
> > not much we can do at this time.
>
> They might have done this following a comment of mine (my memory id fuzzy
> on this, not sure they ever asked). Using the partition type (which is
> just a string) is indeed broken IMO.
Why ? take for example the bootstrap partition, which is Apple_bootstrap on
mac, and 0x41 on chrp/prep MBRs ? The same goes for LVM or RAID partitions.
What is broken is the fact that parted doesn't really supports a way to set
dostypes, and so abuses the partition flags (bootable, hidden, ...) to set the
dostype accordyingly, this leads to some ugly code to assure that some random
dostype flags are removed from the in-memory partition when one of those are
set.
Furthermore, i believe that the partition type is the right place to store
this info, confirmed by the fact that on MBR a type is used for both RAID and
LVM. After all, the fact that a partition does RAID or LVM cannot be
compatible by it being a linux swap partition for example, in the way the
bootable flag is set for example.
I would suggest we use 'Linux_RAID' and 'Linux_LVM' for those two.
> > > this stuff in a second). You can either use a reserved partition type
> > > (again, I don't know what's reserved by Apple there, we use the A/UX
> > > partition type Apple_UNIX_SVR2 to be safe), or stick 'LVM' in the
> > > partition _name_ which can be pretty arbitrary anyway. The d-i partition
> > > editor sets this to 'untitled' when it could well store the mount point
> > > info there, plus 'LVM' for LVM partitions, or other info.
> >
> > Exact, which is the code i proposed to add.
>
> So we should press this point a bit more forcefully :-)
Like said, i will gladly write the (trivial) code, if some consensus is
reached.
> > > Whatever we do, it needs to be coordinated with the other powerpc distros.
> > > I don't know if a new partition type is safe to use; the partition name
> > > definitely is.
> >
> > And was stopped because of this consideration. If i had time, i would say
> > let's lead by example on this one, and the others will follow.
>
> If parted currently encodes the LVM flag in the partition type we can
> still put it into the partition name on top of that, and get the Debian
> LVM maintainer to accept either flag?
No, i would vote against this. After all, a parted user can change the name of
a partition through the parted and d-i/partman interface.
I think that doing it the partition type way is the right thing to do. This is
what is done on x86, and it is what makes the most sense, since if you define
a partition as hosting LVM (or RAID) stuff, you clearly define its type.
Friendly,
Sven Luther
Reply to: