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Re: Upgrade procedure/advice: boot sector



On Sat, 2004-05-22 at 23:58, Jeff Vian wrote:
> Don Levey wrote:
> 
> >I decided that, given a slow weekend, I would upgrade my personal
> >mail/web server from RedHat9 to Fedora2.  Wanting to minimise problems,
> >I did what I hoped would a complete, sector-for-sector copy of the main
> >disk onto another disk of the same geometry using:
> >        dd if=/dev/hda of=/dev/hdb
> >

> >  
> >
> This may be because you said you did a "sector-for-sector copy of the 
> main disk onto another disk of the same geometry using: dd if=/dev/hda 
> of=/dev/hdb"
> This should always work *IF AND ONLY IF* the drives are exactly the same 
> geometry.  That means same physical construciton, and even same make, 
> model, (and maybe even same firmware levels).  If the geometry is not 
> exactly the same it *MAY* work.  
> What you in effect have done is create an exact *byte-for-byte* copy of 
> the drive, including boot sector, partiton table, and even the otherwise 
> inaccessible data that handles LBA mapping, etc.  If this changed 
> information happens to be incompatible with the new hardware it can 
> fail; particularly if the boot sector is not where the drive firmware 
> expects it to be.
> 
Well, they both *say* that they're the same.  It's certainly the same
model and manufacturer, but I guess they could have changed the internal
geometry even if the numbers match up. 

> I assume from what you have said, that the drive is accessible in all 
> ways /except that  it will not boot/.  As such I would suspect a 
> geometry problem that confuses the drive firmware during boot and before 
> Linux gets loaded.
> 
I was just thinking: " I'm curious, though - would this explain being
able to access other files on the disk *except* the boot?" so I guess
the answer would be "yes."

> >Should I:
> >1) Just boot to the Fedora CDs and run the upgrade?  Would this install
> >the boot loader for me? Or...
> >2) Work harder at getting the new disk to boot first, and then do the
> >upgrade?
> >  
> >
> Maybe you should rewrite the partiton table on the new drive and then 
> copy partiton-by-partition to that drive.

That sounds like the next step, I guess.  I may take the time to
readjust the partition sizes, at that point.  None of my family actually
does work on this machine, so having a large /home doesn't seem to make
sense.  However, I've got quite a bit on the web server (family
pictures, and all that) as well as the entire CD collection in a media
directory.  So /var may grow a bit.  Thanks for the help!
 -Don



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