Loader does not load after reinstall with previous mirrored disk attached

Adam Vande More amvandemore at gmail.com
Thu Nov 19 03:06:04 UTC 2009

On Wed, Nov 18, 2009 at 8:35 PM, Glen Barber <glen.j.barber at gmail.com>wrote:

> Hello,
> First off, this is not a real "I need help" post, though there are a
> few questions that I'd like to get insight on, if possible - it is
> more for informative purposes in the archives, should someone run into
> this very random problem in the future. Additionally, I believe this
> is far too unlikely this will happen to many others to consider it to
> be a "problem", thus submitting a PR.
> The story, cut down from its original 3 hour length:
> For some time, I was dual-booting OpenSolaris and FreeBSD, on 500GB
> SATA and 250GB IDE disks, respectively.  When I lost the need to run
> OpenSolaris (Flash), I purchased a second 500GB SATA disk.  I added
> the original SATA disk to gmirror, and synced the 250GB FreeBSD
> install to the 500GB SATA drive.  Once that finished, I removed the
> 250GB disk, and installed the second 500GB disk, adding it to the
> mirror.
> All was fine, except I was not using all of the drive space available.
>  This past weekend, I decided to create a slice to cover the remaining
> 250GB, initially to try ZFS, which failed for the following reason.
> Here is where question 1 comes into play.
> 1.)  What is the correct way to completely break a gmirror setup,
> replacing /dev/mirror/gm0 with the original /dev/adN configuration?
> Is the assumption that once you initialize gmirror, you will never
> need/want to go back to a single disk setup?  Is there a clean way to
> fix boot0 so it does not look for a mirror, short of
> 'vfs.root.mountfrom' in loader.conf?

I usually find this easier to run from fixit cd.  I don't remember exact
order but something like deactivate stop clear.  clear is last for sure
because that will remove metadata.  Remember to change fstab.

Adam Vande More

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