disk recovery help

[Charles Sprickman]

On Tue, 20 Jul 2004, Eitarou Kamo wrote:

> >Here's what fsck says:
> >
> >root at skunkworks[/mnt/tmp/vpopmail/domains]# fsck /dev/vn0c ** /dev/vn0c
> >BAD SUPER BLOCK: VALUES IN SUPER BLOCK DISAGREE WITH THOSE IN FIRST
> >ALTERNATE
> >ioctl (GCINFO): Invalid argument
> >fsck: /dev/vn0c: can't read disk label
> >

> You'd like to do like? :
>
> http://www.freebsd.org/doc/en_US.ISO8859-1/books/handbook/disks-virtual.html

Yes, that allows me to mount the filesystem (but it is still "dirty",
which leads to the occasional panic).

Looking at that first message, fsck is telling me that it sees the
superblock and a superblock backup and that they do not agree.  I know
when you newfs a filesystem there seem to be a ton of superblock backups.
How do I find out where they are and compare them?  Meaning, if the main
one and first backup disagree, but three others all agree can I assume
they are probably right?

> If you'd like to restore dd.img to /dev/da1s1h normally you should
> use dd command directly. dd.img is not a data but just a image.
> So you need not create any file system.

That's what I thought, and that's what I originally tried to do, but after
fdisk'ing and labeling the spare drive to match the original label, dd was
refusing to write to the /dev/ad3s1h device, claiming it was "read only"
(I was root).

Thanks,

Charles

> FYI:
> http://www.freebsd.org/doc/en_US.ISO8859-1/books/handbook/disks.html
>
> Eitarou
>
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