boot sector f*ed

[Jerry McAllister]

On Tue, Aug 11, 2009 at 08:19:24PM +0200, Polytropon wrote:

> On Tue, 11 Aug 2009 13:31:52 -0400, PJ <af.gourmet at videotron.ca> wrote:
> > Sorry for my ignorance, but what language is that? :-)  What's "dd with
> > a bs=1m"?
> 
> That's English + UNIX, at least it should be. :-)
> 
> I could have written "dd with a bs of 1m", which does simply mean that
> the program dd should be called with the parameter bs=1m, representing
> a blocksize of 1 MB. The command would then be:
> 
> 	# dd if=/dev/ad0 of=/dev/ad1 bs=1m
> 
> given the suggestion that ad0 is the source disk, ad1 the target disk.
> It's worth mentioning that the MBR - if intact - should be copied with
> this command (afterwards I think):
> 
> 	# dd if=/dev/ad0 of=/dev/ad1 bs=512 count=1
> 
> Smart dd users will suggest omiting bs=512 because that's the default
> value. :-)
> 
> Finally, commands can be used as verbs, such as "you then dd the ad0
> onto ad1" or "can you grep that in /etc/something"? :-)

Nice response, but don't forget to have the OP read the man page --
eg    man dd

////jerry


> 
> 
> > I'm being ultra careful and checking/regenerating the target disk and
> > that will t ake another 4 or 5 hours.
> 
> That's the usual amount of time. I think you said approx. 100 GB disks?
> It may work faster if you don't run the transfer in master / slave mode
> (same cable), but in master / master mode (each drive on own cable);
> this affects (P)ATA only, as far as I know.
> 
> 
> 
> > I don't expect any difficulties,
> > but would like to "triple check" the procedure...
> > 
> > Ok - boot up livefs, slice & partition the target disk; but how do I
> > continue? Do I go to the shell?
> 
> Yes. You can either use the shell of FreeBSD's live system, or use
> FreeSBIE, it has sysinstall on it, too, as far as I remember. But
> nobody stops you from not using sysinstall, but bsdlabel and newfs
> instead.
> 
> Keep an eye on newfs options, especially if you want to enable soft
> updates or with to init the disks with a certain optimization, or
> a non-default inode ratio.
> 
> 
> 
> > If that is all it is, then I don't see
> > much difficulty. I'll read the man pages to check all the commands below
> > so I am clear on everything.
> 
> That's a good idea. I copied the command line examples from a procedure
> I once wrote for how to "clone" OS disks.
> 
> 
> 
> > If it is, do I need it or what do I do with it? It is obviously(?) saved
> > somewhere like /tmp ...
> 
> The kernel image is saved in /var/crash directory. It can be used for
> examination, in order to find out what caused the crash. Usually, the
> kernel debugger is employed to do this. If you don't care any further,
> you can safely delete the core files.
> 
> 
> 
> 
> -- 
> Polytropon
> >From Magdeburg, Germany
> Happy FreeBSD user since 4.0
> Andra moi ennepe, Mousa, ...
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