Re: problem with wedges

[Jean-Yves Migeon <jeanyves.migeon%free.fr@localhost>]

On 01.05.2010 16:03, Jukka Marin wrote:
> > > However, I can't access dk0:
> > >
> > > # gpt show dk0
> > > gpt: unable to open device ': No such process
> > > # dkctl dk0 listwedges
> > > dkctl: dk0: listwedges: Inappropriate ioctl for device
> > > # disklabel dk0
> > > disklabel: ioctl DIOCGDINFO: Inappropriate ioctl for device
> >
> > # gpt show xbd1
> > # dkctl xbd1 listwedges
> >
> > I do not understand what you want to get access to: a GPT partition? MBR
> > partition? A disklabel?
>
> Previously, dom0 supplied /dev/dk0 to domU for xbd1 and domU then mounted
> /dev/xbd1d as /media (ffs).

This dk0 wedge was obtained/detected from what? Wedges are MI 
representations of partitions, and are created either manually or 
automagically through the information it can get in a MBR, GPT or disklabel.

> Now, dom0 gives the raw disk (sdh) to domU which detects the gpt/wedge and
> attaches dk0.

The dk0 created here comes from GUID 
"c1349a02-e045-11dc-96ed-003048928bca" of the GPT on xbd1, which is 
probably the one you get from the GPT accessible on sdh in dom0. That 
does not mean it corresponds to the wedge you had previously in your domU.

> I want to access the data on dk0, but I'm not sure what I'm doing wrong.
>
> > What did you use to partition xbd1?
>
> I can't access my own wedge related notes right now and it was maybe 1.5
> years ago when I created the disk.  It is using gpt and wedges because
> the normal disklabel does not work with disks this large.
>
> The disk has about 3 TB of data which I do not want to lose...

When you had a NetBSD dom0, the dk0 was necessarily created manually or 
automagically from a GPT (I suppose that the dk in question was > 2TB).

IIUC, you have two level of indirection here: one where you were using a 
dk0 wedge as a xbd for your domU, and then, this xbd was partitioned 
inside your domU so that you could mount xbd1d as /media.

In that case:

- where did this dk0 comes from for dom0?
If it comes from the GPT found on the "sdh" Linux disk, you have to find 
the associated partition (sdh[number]), and pass that to your domU 
config file. Or find a way so that Linux creates the proper device to 
access it.

- what did you use to partition the associated xbd within domU?

--
Jean-Yves Migeon
jeanyves.migeon%free.fr@localhost