8.0-Beta installation problem -- Unable to find /dev/ad0s1b

Polytropon freebsd at edvax.de
Mon Sep 14 22:12:03 UTC 2009

On Mon, 14 Sep 2009 14:08:53 -0700 (PDT), Jin Guojun <jguojun at sbcglobal.net> wrote:
> I do not enve know how to make "dangerously dedicated" disk,
> and the 8.0 may do this sliently.

This term refers to a disk where no "DOS primary partition",
i. e. a slice, has been created. Usually, for a disk with
only FreeBSD on it, you first take a disk


create a slice


and put partitions into it (or just one partition), like

	/dev/ad0s1a = /
	/dev/ad0s1b = swap
	/dev/ad0s1d = /tmo
	/dev/ad0s1e = /var
	/dev/ad0s1f = /usr
	/dev/ad0s1g = /home

or something similar. In "dangerously dedicated" mode, you
omit the slice creation and create the partitions on the
disk device /dev/ad0, so you end up with

	/dev/ad0a = /
	/dev/ad0b = swap
	/dev/ad0d = /tmo
	/dev/ad0e = /var
	/dev/ad0f = /usr
	/dev/ad0g = /home

Using such mode is common for data disks, but not for disks
you boot from.

> ad0 had three DOS partitions (slices),
> S1 for DOS
> S2 for FreeBSD 7.2
> S3 for another FreeBSD
> When boot to 8.0-Beta{3, 4}, 8.0 sees not partition, which means
> 8.0 looked at a wrong location for partition table.

What does the "fdisk" command report?

> After did partition (slices S1 for FreebSD and S2 for nothing) and 
> Label (Unix partitions, failed to find device node /dev/ad0s1b in /dev),
> content of 7.2 is gone.

Seems to be correct up to here; /dev/ad0s1b refers to the swap

> But, the original partitions are still in the MBR (S1 for DOS, and
> S2 and S3 for FreeBSD).

So an update of the MBR hasn't taken place?

Magdeburg, Germany
Happy FreeBSD user since 4.0
Andra moi ennepe, Mousa, ...

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